Factors Associated With the Accuracy of Depth Gauge Measurements

Background: It is important to select appropriate screws in orthopedic surgeries, as excessively long or too short a screw may results failure of the surgeries. This study explored factors that affect the accuracy of measurements in terms of the experience of the surgeons, passage of drilled holes and different depth gauges.Methods: Holes were drilled into fresh porcine femurs with skin in three passages, straight drilling through the metaphysis, straight drilling through the diaphysis, and angled drilling through the diaphysis. Surgeons with different surgical experiences measured the holes with the same depth gauge and using a vernier caliper as gold standard. The length of selected screws, and the time each surgeon spent were recorded. The measurement accuracy was compared based on the experiences of the surgeons and the passage of drilled holes. Further, parameters of depth gauges and 12-mm cortical bone screws from five different manufacturers were measured.Results: A total of 13 surgeons participated in 585 measurements in this study, and each surgeon completed 45 measurements. For the surgeons in the senior, intermediate, and junior groups, the average time spent in measurements was 689, 833, and 785 s with an accuracy of 57.0, 42.2, and 31.5%, respectively. The accuracy and measurement efficiency were significantly different among the groups of surgeons (P < 0.001). The accuracy of measurements was 45.1% for straight metaphyseal drilling, 43.6% for straight diaphyseal drilling, and 33.3% for angled diaphyseal drilling (P = 0.036). Parameters of depth gauges and screws varied among different manufacturers.Conclusion: Both observer factor and objective factors could affect the accuracy of depth gauge measurement. Increased surgeon's experience was associated with improvements in the accuracy rate and measurement efficiency of drilled holes based on the depth gauge. The accuracy rate varied with hole passages, being the lowest for angled drilled holes.

Effect of Bidirectional Insertion of External Skeletal Fixation Pins on Axial Pullout Strength in Canine Cadaveric Bone

Objective The aim of this study was to evaluate the effect of bidirectional insertion on axial pullout strength of tapered run out (TRO), traditional negative profile (TNP) and positive profile (PP) pins. Study Design Cadaveric adult canine tibiae were harvested. Tapered run out pins (Group 1) were inserted unidirectionally to the desired position; bidirectionally past the desired position, then withdrawn to the desired position (Group 2); and bidirectionally as described for Group 2, repeated twice (Group 3). Traditional negative profile pins (Group 4–6) and PP pins (Group 9–11) were placed in the same manner. Tapered run out (Group 7), TNP (Group 8) and PP pins (Group 12) were driven unidirectionally such that the shaft of the pin violated the cis-cortex. A servohydraulic testing machine extracted the pins and measured axial peak pullout strength. Results Positive profile pins had significantly greater pullout strength than TRO and TNP pins placed unidirectionally to the desired position. Method of insertion had no effect on peak pullout strength of TNP pins. TRO and PP pins inserted unidirectionally to the desired position had significantly greater peak pullout strengths than insertion bidirectionally or if the shaft of the pin violated the cis-cortex. Conclusion The authors recommend that pins used for external skeletal fixation should be placed unidirectionally to the desired position with fluoroscopic guidance, intra-operative depth gauge measurements or measurements from preoperative radiographs. Repositioning pins results in loss of peak pullout strength with TRO and PP pins.

Modification of Portable Power Tiller for Small Scale Weeding Operation

Weeds are unwanted and undesirable plant that interfere with the utilization of land and water resources and adversely affect crop production. After preliminary study, it was found out that power tiller could be adopted for weeding. Therefore, the study aimed at improving its performance through modification of some major component such as: weeding blades and depth gauge. Three sets of pairs of blade gang of four, six and eight were made from 3 mm mild steel sheet metal. The fabrication was carried out at the Department of Agricultural and Bio-Resources Engineering, Ahmadu Bello University, Zaria. The modified machine was evaluated based on weeding efficiency, field capacity, Plant Damage and Fuel consumption in the maize field during 2017/2018 irrigation season at Institute for Agricultural Research, IAR, Ahmadu Bello University, Zaria research farm. Four levels of blade types ‘B’ and three levels of weeding depth ‘D’ were considered. The field was laid in a 4×3 Randomized Complete Block Design (RCBD) at two (2) Weeks After Sowing (2WAS). DMRT was used for mean separation ran in SAS package. The results showed effects of blade types and weeding depth were significant on the weeding performance of the machine.

Kondisi Terumbu Karang di Perairan Gili Gede, Sekotong Lombok Barat

Protection and sustainable data collection are very important in order to protect the coral reef ecosystem. This research was conducted to monitor and determine the condition of coral reefs in the eastern part of Gili Gede Island, which is administratively located in Sekotong Sub-District, West Lombok Regency, NTB. The method used is Line Intercept Transect (LIT). Furthermore, the starting point of the transect stretch is recorded using GPS coordinates and the depth gauge is used to estimate the depth of the water. The results showed that the status of coral reefs tended to be badly damaged with the mean value of all stations (21.92%). Fishery activities and pressure from the land are thought to be several factors that tend to affect the poor coastal ecosystem

Bathymetric, Physicochemical and Microbiological Analyses of Sarikum Lake (Sinop-Turkey)

Sarikum Lake located in the protected area of Sarikum Village boundaries of Sinop Province Central District was investigated in terms of bathymetric, physicochemical and microbiological aspects. This study was carried out between October 2017 and March 2018. For bathymetric analysis, a Garmin echo 551 c brand dual frequency depth gauge (echo sounder) and 2 GPS receivers were used. For pollution parameters, water samples were taken from stations determined at 3 different points of the lake. Parameters such as temperature, Total Dissolved Solids (TDS), salinity, electrical conductivity, Oxidation Reduction Potential (ORP) and pH were measured with the multifunctional meter during sampling. In addition, ammonia nitrogen (NH4+-N), iron (Fe), phosphate phosphorus (PO43--P), manganese (Mn), nitrite nitrogen (NO2 --N), nitrate nitrogen (NO3- -N) and total hardness (Ethylene Diamine Tetra (EDTA) titrimetric) according to standard methods (Apha, Awwa, Wef, 2005). Total coliform, E. coli, fecal streptococcus, fecal coliform, sulfide reducing anearob and Clostridium perfringes analyzes were performed for microbiological analyses. Sulfide reducing anaerobes were not detected in the assay results. Based on the obtained results, it is determined that Sarikum Lake within the sanctuary area of Sarikum Village of Sinop province (Turkey) is close to the dirty / pollution limit according to the inland field regulations.

Investigating fecundity and egg loss using a non-invasive method during brooding in European lobster (Homarus gammarus)

This article examines two important components of measurement of fecundity in the European lobster Homarus gammarus: (i) comparing the traditional gravimetric dry weight fecundity method against two non-invasive depth gauge methods initially developed for Homarus americanus and (ii) utilizing the depth gauge method to determine egg loss during the brooding period and its impacts on effective fecundity estimates. No significant difference was observed between fecundity estimates derived using either the traditional or depth gauge methods. Derived fecundity estimates from the two depth gauge methods differed by −0.31% (±2.7 s.e.) for cylinder and −1.1% (±2.4 s.e.) for ellipsoid fecundity estimates compared with the traditional method. This highlights the utility of the depth gauge method for providing fast, reliable and low-cost estimates without sacrificing lobsters or their egg masses. Egg loss is estimated to be as high as 44% from initial extrusion to hatching. The application of the non-invasive methods for estimating fecundity to other fisheries and stocks is discussed along with the importance of understanding egg loss in this commercially valuable fishery.

Bedding-parallel stylolites as a tool to unravel maximum burial depth in sedimentary basins: Application to Middle Jurassic carbonate reservoirs in the Paris basin, France

In recent years stylolites, which are rough dissolution surfaces commonly found in carbonates, have been used for paleopiezometry estimates. The Stylolite Roughness Inversion Technique (SRIT) applied on sedimentary bedding-parallel stylolites (BPS) grants access to the maximum principal vertical stress experienced by the host carbonates and thus to their maximum burial paleo-depth. This study reports the results of SRIT applied to a BPS population hosted in carbonate platform reservoirs of the Paris basin sub-surface (France). Middle Jurassic carbonates from two well cores from the depocenter and margin of the basin, for which the burial and thermal history are known, based on a thermally calibrated 3-D basin model, were analyzed. By defining a consistency criterion and using two signal treatment methods, we propose a new approach to select which BPS can be reliably used to reconstruct the maximum vertical stress undergone by the host carbonates, which then can be converted into maximum burial depth. The study of a BPS population shows that there is a control operated by the host rock texture and the stylolite morphology on the burial depth recorded. Especially suture and sharp peak BPS are better suited to estimate the real maximum depth, whereas seismogram pinning BPS record preferentially intermediate depths. Median values of maximum depth derived from our data set (1300 and 1650 m for the margin and depocenter cores, respectively) are in line with maximum burial estimates provided by conventional basin modeling (1450 and 1800 m, respectively), thus showing that SRIT is a standalone robust depth gauge in sedimentary basins, provided sample selection and data treatment are carried out in a rigorous and thoughtful manner.