Manual Scaling Research Articles

Comparison between manual scaling and Autoscala automatic scaling applied to Sodankylä Geophysical Observatory ionograms

Abstract. This paper presents a comparison between standard ionospheric parameters manually and automatically scaled from ionograms recorded at the high-latitude Sodankylä Geophysical Observatory (SGO, ionosonde SO166, 64.1° geomagnetic latitude), located in the vicinity of the auroral oval. The study is based on 2610 ionograms recorded during the period June–December 2013. The automatic scaling was made by means of the Autoscala software. A few typical examples are shown to outline the method, and statistics are presented regarding the differences between manually and automatically scaled values of F2, F1, E and sporadic E (Es) layer parameters. We draw the conclusions that: 1. The F2 parameters scaled by Autoscala, foF2 and M(3000)F2, are reliable. 2. F1 is identified by Autoscala in significantly fewer cases (about 50 %) than in the manual routine, but if identified the values of foF1 are reliable. 3. Autoscala frequently (30 % of the cases) detects an E layer when the manual scaling process does not. When identified by both methods, the Autoscala E-layer parameters are close to those manually scaled, foE agreeing to within 0.4 MHz. 4. Es and parameters of Es identified by Autoscala are in many cases different from those of the manual scaling. Scaling of Es at auroral latitudes is often a difficult task.

Three-dimensional computational fluid dynamics modeling of particle uptake by an occupational air sampler using manually-scaled and adaptive grids

This work presents fluid flow and particle trajectory simulation studies to determine the aspiration efficiency of a horizontally oriented occupational air sampler using computational fluid dynamics (CFD). Grid adaption and manual scaling of the grids were applied to two sampler prototypes based on a 37-mm cassette. The standard k–ε model was used to simulate the turbulent air flow and a second order streamline-upwind discretization scheme was used to stabilize convective terms of the Navier–Stokes equations. Successively scaled grids for each configuration were created manually and by means of grid adaption using the velocity gradient in the main flow direction. Solutions were verified to assess iterative convergence, grid independence and monotonic convergence. Particle aspiration efficiencies determined for both prototype samplers were undistinguishable, indicating that the porous filter does not play a noticeable role in particle aspiration. Results conclude that grid adaption is a powerful tool that allows to refine specific regions that require lots of detail and therefore better resolve flow detail. It was verified that adaptive grids provided a higher number of locations with monotonic convergence than the manual grids and required the least computational effort.

Ocular injury during scaling: Are we protecting ourselves?

The risk of ocular injury in dentistry is mainly attributed to the use of power driven high speed Handpieces and ultrasonics. These ocular injuries may vary from mild irritation to grave implications such as blindness. Various studies have reported about such injuries and their consequences. The guidelines are laid by health associations regarding protective eyewear use during dental procedures. This study emphasizes about the need to protect the eye with protective eye wear, failing which a dental student suffered a serious ocular injury while performing manual scaling procedure.

Working position influences the biomechanical demands on the lower back during dental hygiene

This investigation monitored the biomechanical demands on the lower back during simulated dental hygiene work. A total of 19 female, registered dental hygienists performed 30 continuous minutes of manual scaling (plaque removal) of a manikin’s teeth while seated. We monitored the working location and orientation of the dental hygienists, with respect to the manikin, along with their spine kinematics, spine extensor muscle activities and seat pressure, throughout the 30 min. A clock representation was used to express the working location. The location significantly influenced the dental hygienists’ pelvic orientation with respect to the manikin, spine posture, erector muscle activity and pressure distribution. Findings from this study suggest that the prevalence of lower back pain amongst dental hygienists may be directly related to low-level tonic activity of the spine’s extensor musculature, and the combined flexed and axially rotated spine postures.Practitioner Summary:Low back pain (LBP) is prevalent in dental hygienists, yet occupational demand on the low back has not been investigated. Posture, muscle activity and seat pressure were monitored. Combined spine rotation and flexion, and tonic activity of the extensor musculature may be related to LBP in dental hygienists.

Treatment of periodontal disease with an Er,Cr:YSGG laser in rats exposed to cigarette smoke inhalation.

The purpose of this study was to evaluate the erbium, chromium:yttrium-scandiumgallium-garnet (Er,Cr:YSGG) laser irradiation in the treatment of periodontitis in rats exposed to cigarette smoke inhalation (CSI). Ligatures were placed in the maxillary second molars. After a 15-day period, the ligatures were removed and 180 animals were randomly divided into six groups: (1) CSRP group--CSI and manual scaling and root planing (SRP) treatment; (2) CL group--CSI and Er,Cr:YSGG laser irradiation; (3) CSRP + L group-CSI, SRP, and Er,Cr:YSGG irradiation; (4) SRP group-manual SRP; (5) L group--Er,Cr:YSGG irradiation; (6) SRP + L group--SRP and Er,Cr:YSGG irradiation. At 7, 15, and 30 days after treatments, animals were euthanized and histologic, histometric, immunohistochemistry, and real-time PCR analyses were performed. Histometrically, no differences were observed in the SRP, L, and SRP + L groups exposed to CSI. The CSRP group showed more bone formation at 30 days than at 15 days (p < 0.01) but less bone at 30 days than the CL group at 30 days (p < 0.05). Immunohistochemical staining was positive for osteoblasts, fibroblasts, and osteoclasts. Real-time PCR showed more (vascular endothelial growth factor) VEGF expression in the L (p < 0.05) and SRP + L (p < 0.01) groups at 30 days than at 15 days and less VEGF expression in the CSRP group at 30 days than at 15 days (p < 0.05). There was no difference in fibroblast growth factor (FGF) expression. The Er,Cr:YSGG laser irradiation promotes favorable conditions for tissue repair even in animals exposed to CSI, with similar results as those achieved from manual scaling and root planing.

Effect of Er,Cr:YSGG laser application in the treatment of experimental periodontitis

The purpose of this study was to evaluate the influence of an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser in the absence or presence of manual scaling and root planning (SRP) for the treatment of induced periodontitis in rats. Ligatures were placed in the subgingival region of the maxillary first molar. After a 7-day period, the ligatures were removed, and 40 rats were randomly divided into four groups (G), as follows: (GI) no treatment, (GII) scaling and root planning (SRP) with curettes, (GIII) Er,Cr:YSGG laser irradiation and (GIV) SRP with curettes followed by Er,Cr:YSGG laser irradiation. Seven and 30 days after the treatment, the animals were sacrificed and histologic, histometric and immunohistochemistry analyses were performed. All groups showed similar histopathological characteristics during the evaluation period. The histometric analysis was confirmed using Bonferroni and paired t tests. At 7 and 30 days, groups II, III and IV exhibited greater bone formation in the furcation area when compared to group I (p < 0.0001; p < 0.05). During the 7-day period, the groups irradiated with the laser (III and IV) showed a statistically larger new bone area than the group treated with SRP (II) (p < 0.01). Immunohistochemistry analysis revealed that the control group exhibited a higher expression of tartrate-resistant acid phosphatase (TRAP) and the receptor activator of nuclear factor κΒ ligand (RANKL) when compared to groups II, III and IV (p < 0.05). All treatments were able to reduce the inflammatory processes, consequently enabling the repair of periodontal tissues. The results achieved with the application of the Er,Cr:YSGG laser suggest that this laser can stimulate greater bone formation, especially over a shorter period of time.

A demonstration-based model transformation approach to automate model scalability

An important aspect during software development is the ability to evolve and scale software models in order to handle design forces, such as enlarging and upgrading system features, or allocating more resources to handle additional users. Model scalability is the ability to refactor a base model, by adding or replicating the base model elements, connections or substructures, in order to build a larger and more complex model to satisfy new design requirements. Although a number of modeling tools have been developed to create and edit models for different purposes, mechanisms to scale models have not been well supported. In most situations, models are manually scaled using the basic point-and-click editing operations provided by the modeling environment. Manual model scaling is often tedious and error-prone, especially when the model to be scaled has hundreds or thousands of elements and the scaling process involves entirely manual operations. Although model scaling tasks can be automated by using model transformation languages, writing model transformation rules requires learning a model transformation language, as well as possessing a great deal of knowledge about the metamodel. Model transformation languages and metamodel concepts are often difficult for domain experts to understand. This requirement to learn a complex model transformation language exerts a negative influence on the usage of models by domain experts in software development. For instance, domain experts may be prevented from contributing to model scalability tasks from which they have significant domain experience. This paper presents a demonstration-based approach to automate model scaling. Instead of writing model transformation rules explicitly, users demonstrate how to scale models by directly editing the concrete model instances and simulate the model replication processes. By recording a user's operations, an inference engine analyzes the user's demonstration and generalizes model transformation patterns automatically, which can be reused to scale up other model instances. Using this approach, users are able to automate scaling tasks without learning a complex model transformation language. In addition, because the demonstration is performed on model instances, users are isolated from the underlying abstract metamodel definitions.

Approach of Industrial Physical Therapy to Assessment of the Musculoskeletal System and Ergonomic Risk Factors of the Dental Hygienist

This study aimed to provide fundamental data to be utilized in preventing and treating musculoskeletal disorders and analyzing working postures commonly used during periodontal treatment. [Subjects] The subjects were three dental hygienists with work experience in dental clinics for more than 10 years. [Methods] For the analysis of working postures, we simulated the work posture of dental hygienists during the scaling procedures and oral radiographic imaging tasks. The subjects were recorded on video to precisely observe them while they were working. The captured working postures were assessed and analyzed using ergonomic assessment methods, the Rapid Entire Body Assessment, Rapid Upper Limb Assessment, and Strain index. [Results] No differences were exhibited in the intensities of manual scaling and ultrasonic scaling. Commonly, the shoulders and waist were found to be the most overburdened. According to the strain index, manual scaling and ultrasonic scaling working postures were identified to be most dangerous. [Conclusion] The work postures of dental hygienists during scaling are postures that are highly likely to generate work-related musculoskeletal disorders. Therefore, the development of therapeutic exercise programs easily performable in the workplace and daily life is thought to be crucial to prevent work-related musculoskeletal disorders.

Adjunctive effect of chlorhexidine antiseptics in mechanical periodontal treatment: first results of a preliminary case series

The aim of the present case series was to evaluate the clinical and microbiological effects of a single session of mechanical and manual scaling and root planing (SRP) combined with the use of two different chlorhexidine formulations in the treatment for generalized chronic periodontitis. Ten patients affected by chronic periodontal disease with periodontal probing depth (PPD) ≥ 5 mm were treated with SRP plus local chlorhexidine. In each patient, similar teeth, treated with SRP with the adjunctive use of chlorhexidine digluconate and dihydrochloride or chlorhexidine gluconate, respectively, were selected and assigned to a test and a control group. In both groups, PPD, bleeding on probing (BOP) parameters, total bacterial counts (TBC) and quality of periodontal bacteria at time 0 and 6 weeks after treatment were measured. PPD significantly decreased over time both in the test and in the control group; however, no significant differences between the two groups were observed. BOP and TBC were significantly lower in the test than in the control group 6 weeks after treatment. In the post-treatment revaluation, a significant decrease both in the treatment and in the control group, for each of the single periodontal pathogens, was observed. In this study--a preliminary case series with small sample size and short follow-up--the adjunctive use of chlorhexidine (CHX) to SRP resulted in clinical and microbiological benefits in the treatment for generalized chronic periodontitis. A CHX gel formulation consisting of CHX digluconate and CHX dihydrochloride seems to lead some additional benefits over SRP plus CHX gluconate in the short term. Additional investigations are needed to evaluate the effectiveness of this antiseptic therapy.

Clinical Outcomes After Nonsurgical Periodontal Therapy with an Er:YAG Laser Device: A Randomized Controlled Pilot Study

The purpose of this study was to compare the short-term effects of nonsurgical periodontal treatment with the short-term effects of Er:YAG laser debridement (ERL) and manual scaling and root planning (SRP) in nonsmoking patients with chronic periodontitis. Nineteen nonsmoking patients (mean age 60.7) with chronic generalized periodontitis were randomly treated with ERL or SRP in a split-mouth design. Clinical attachment level (CAL), periodontal pocket depth (PPD), and bleeding on probing (BOP) were recorded. Immediately after completion of the treatment procedure, patients used a visual analogue scale (VAS) to grade the degree of discomfort experienced during treatment. Both groups showed significant reductions in their PPD, CAL, and BOP values 2 months after treatment. The sites treated with Er:YAG laser demonstrated mean PPD changes that varied from 5.00 ± 0.63 to 3.54 ± 0.83 mm, mean CAL changes that varied from 5.19 ± 0.69 to 3.86 ± 0.94 mm, and BOP changes that varied from 26.57 ± 12.54 to 13.17 ± 7.52 mm. Sites treated with manual SRP demonstrated mean PPD changes that varied from 4.91 ± 0.55 to 3.51 ± 0.98 mm, mean CAL changes that varied from 5.08 ± 0.59 to 3.95 ± 1.16 mm, and BOP values that varied from 24.81 ± 7.65 to 15.41 ± 6.32 mm. Comparison of the two techniques demonstrated the statistically significant superiority of Er:YAG only for the CAL scores (p<0.05). Within the limits of this study, ERL may be posited as an alternative to mechanical treatment in the management of chronic periodontitis. In addition, ERL may be performed on patients who are sensitive to the use of injectable anesthetics. Future studies, with larger samples, are needed to determine the long-term clinical outcomes of ERL.

Improving the automatic inversion of digital Alouette/ISIS ionogram reflection traces into topside electron density profiles

The topside sounders of the International Satellites for Ionospheric Studies (ISIS) program were designed as analog systems. The resulting ionograms were displayed on 35 mm film for analysis by visual inspection. Each of these satellites, launched between 1962 and 1971, produced data for 10 to 20 years. A number of the original telemetry tapes from this large data set have been converted directly into digital records. Software, known as the Topside Ionogram Scalar With True‐Height (TOPIST) algorithm, has been produced and used for the automatic inversion of the ionogram reflection traces on more than 100,000 ISIS‐2 digital topside ionograms into topside vertical electron density profiles Ne(h). Here we present some topside ionospheric solar cycle variations deduced from the TOPIST database to illustrate the scientific benefit of improving and expanding the topside ionospheric Ne(h) database. The profile improvements will be based on improvements in the TOPIST software motivated by direct comparisons between TOPIST profiles and profiles produced by manual scaling in the early days of the ISIS program. The database expansion will be based on new software designed to overcome limitations in the original digital topside ionogram database caused by difficulties encountered during the analog‐to‐digital conversion process in the detection of the ionogram frame sync pulse and/or the frequency markers. This improved and expanded TOPIST topside Ne(h) database will greatly enhance investigations into both short‐ and long‐term ionospheric changes, e.g., the observed topside ionospheric responses to magnetic storms, induced by interplanetary magnetic clouds, and solar cycle variations, respectively.

Physical workload in neck, shoulders and wrists/hands in dental hygienists during a work-day

Physical workload was recorded by electromyography, inclinometry and goniometry for twelve female dental hygienists during authentic work. Their work was, in relation to other types of work, characterised by pronounced head flexion (90th percentile 46°), high loads on the forearm extensor muscles (90th percentile 23% and 18% of maximal EMG (MVE), for the right and left sides, respectively), average loads on trapezius muscles (90th percentile 15% and 14% MVE), average arm elevation (99th percentile 83° and 72°) and average wrist flexion and velocities (50th percentiles 17° of extension and 7.3°/s, for the right side). Manual scaling and machinery (use of ultrasonic scaling and hand-pieces) showed higher loads on the trapezius muscles, regarding muscular rest, as well as the 10th and 50th percentiles, than the other tasks, and for the forearm extensor muscles, an almost complete lack of muscular rest (0.1% time), and much higher loads regarding the 10th and 50th percentiles. Further, more pronounced head flexion and lower head and upper arm velocities were found, indicating more constrained postures for the neck and shoulders for the manual scaling and machinery. Use of ultrasonic scaler reduced the 50th percentile loads on the right forearm extensor muscles, but had no effect on the fraction of muscular rest and on the 10th percentile load. These findings are consistent with the high prevalences of musculoskeletal disorders among dental hygienists.

A scanning electron microscopy study of diseased root surfaces conditioned with EDTA gel plus Cetavlon after scaling and root planing

In the present investigation, a scanning electron microscopy analysis was performed to evaluate the effects of the topical application of ethylenediaminetetraacetic acid (EDTA) gel associated with Cetavlon (EDTAC) in removing the smear layer and exposing collagen fibers following root surface instrumentation. Twenty-eight teeth from adult humans, single rooted and scheduled for extraction due to periodontal reasons, were selected. Each tooth was submitted to manual (scaling and root planing) instrumentation alone or combined with ultrasonic instruments, with or without etching using a 24% EDTAC gel. Following extraction, specimens were processed and examined under a scanning electron microscope. A comparative morphological semi-quantitative analysis was performed; the intensity of the smear layer and the decalcification of cementum and dentinal surfaces were graded in 12 sets using an arbitrary scale ranging from 1 (area covered by a smear layer) to 4 (no smear layer). Root debridement with hand instruments alone or combined with ultrasonic instruments resulted in a similar smear layer covering the root surfaces. The smear layer was successfully removed from the surfaces treated with EDTAC, which exhibited numerous exposed dentinal tubules and collagen fibers. This study supports the hypothesis that manual instrumentation alone or instrumentation combined with ultrasonic instrumentation is unable to remove the smear layer, whereas the subsequent topical application of EDTAC gel effectively removes the smear layer, uncovers dentinal openings and exposes collagen fibers.

Effect of periodontal therapies on indirect restoration: a scanning electron microscopic analysis

The aim of this study was to evaluate the influence of different periodontal therapies on the integrity of indirect restorations by scanning electron microscopy (SEM). Sixty single-rooted bovine teeth were selected and randomly assigned to 12 groups. Inlay cavities were prepared in the cervical region on the center of the cementoenamel junction, and were restored with laboratory processed resin and luted with a resin cement. Twelve periodontal therapies were used (n= 5): C: control (no treatment); MS: manual scaling with Gracey curettes; US: ultrasonic scaling; PP: prophylaxis with prophylactic paste; PS: prophylaxis with pumice-stone; SBJ: sodium bicarbonate jet; MS/PP; MS/PS; MS/SBJ; US/PP; US/PS; US/SBJ. The specimens were prepared and analyzed by SEM. SEM micrographs at x100 to x1000 magnification were obtained from the surface of the laboratory resin and the interface of the indirect restorations. The images were evaluated by 3 skillful, calibrated, blinded observers as to the presence of grooves, microcavities and fracture of margins. The results showed that PS produced groves on restoration surface. MS and US produced groves and marginal fractures on the restorations. SBJ resulted in resin cement degradation. These results suggest that except for PS, all procedures had deleterious effects on the marginal integrity of indirect restorations.

Effect on pocket depth and attachment level of manual versus ultrasonic scaling of lower second molars following lower third molar extraction: a randomized controlled trial

The objective of this study was to compare the effect on periodontal health of ultrasonic versus manual scaling of the lower second molar (L2M) root surface following surgical extraction of mesioangular lower third molars (L3M). Randomized single-blind clinical trial to compare the effectiveness of ultrasonic scaling of the L2M (experimental group) and manual scaling and root planing (control group) after surgical extraction of the corresponding L3M. Forty-three subjects were enrolled, 69.8% completing the study. The postoperative bony defect on the distal surface of the L2M was significantly reduced for both treatment groups (P = .001). Despite a higher reduction of intrabony defect being observed in the ultrasonic group, the difference was not significant (P = .17) at 6 months. Furthermore, there was also no statistically significant correlation (P > .05) between the postoperative pocket depth and the treatment group (ultrasonic or manual). Pocket depth and depth of the intrabony defect were similar in both experimental and control groups.

Observations on the Effects of Scaling and Polishing Methods on Enamel

This study compared several techniques of manual and power instrument supragingival scaling and subsequent polishing with different methods. Observations were made to determine if there was an optimal method of enamel surface treatment based on the efficacy of the polishing and damage to the enamel. The maxillary fourth premolar and canine teeth were used as experimental teeth. These teeth were extracted after treatment and immersed in 10% buffered formalin solution for further processing and evaluation using electron microscopy. Our observations indicated that the most effective method for scaling and enamel protection during periodontal treatment was provided by power instrumentation followed by polishing using a soft polishing wheel with pumice paste.

In vitro evaluation of the effect of natural orange juices on dentin morphology

The patient's diet has been considered an important etiological factor of dentin hypersensitivity. The frequent ingestion of acidic substances can promote the loss of dental structure or remove the smear layer. The purpose of this study was to evaluate the degree of smear layer removal and dentinal tubules exposure by different natural orange juices. Extracted human teeth were submitted to manual scaling in order to develop the smear layer. Seventy dentin samples were obtained and distributed into the following groups: Control, lime orange, lime, valência orange, navel orange, mandarin, and tangerine. Each group included 2 methods of application: Topical and topical + friction. After preparation for SEM analysis, photomicrographs were assessed by a blind calibrated examiner using an index system. The Kruskal-Wallis test indicated a significant influence of the orange juices on smear layer removal. Significant difference was observed between navel orange, valência orange, mandarin and the control group (p < 0.05). These orange juices resulted in greater removal of the smear layer and greater opening of dentinal tubules. The comparison between the application methods for each group using the Mann-Whitney test showed that friction increased smear layer removal significantly only for lime orange and lime. The data suggest that certain natural orange juices are more effective in terms of smear layer removal and dentinal tubules exposure than others.

First assimilations of COSMIC radio occultation data into the Electron Density Assimilative Model (EDAM)

Abstract. Ground based measurements of slant total electron content (TEC) can be assimilated into ionospheric models to produce 3-D representations of ionospheric electron density. The Electron Density Assimilative Model (EDAM) has been developed for this purpose. Previous tests using EDAM and ground based data have demonstrated that the information on the vertical structure of the ionosphere is limited in this type of data. The launch of the COSMIC satellite constellation provides the opportunity to use radio occultation data which has more vertical information. EDAM assimilations have been run for three time periods representing quiet, moderate and disturbed geomagnetic conditions. For each run, three data sets have been ingested – only ground based data, only COSMIC data and both ground based and COSMIC data. The results from this preliminary study show that both ground and space based data are capable of improving the representation of the vertical structure of the ionosphere. However, the analysis is limited by the incomplete deployment of the COSMIC constellation and the use of auto-scaled ionosonde data. The first of these can be addressed by repeating this type of study once full deployment has been achieved. The latter requires the manual scaling of ionosonde data; ideally an agreed data set would be scaled and made available to the community to facilitate comparative testing of assimilative models.

A comparison between the hourly autoscaled and manually scaled characteristics from the Chilton ionosonde from 1996 to 2004

Most monitoring ionosonde stations now rely on automatic processing rather than manual processing to provide ionospheric characteristics. A systematic assessment was made of the quality of all the key ionospheric characteristics scaled automatically from hourly ionograms from the midlatitude Chilton ionosonde in the United Kingdom, by comparing them with the definitive values produced by manual scaling. The data for the study were a nearly continuous series of hourly values covering the majority of solar cycle 23 from 1996 to the end of 2004. This period includes solar maximum and minimum conditions and quiet and disturbed intervals, and the investigation is the first comprehensive examination of the performance of automatic scaling without any data preselection over such an extended period. The accuracy of autoscaled values during storm periods was examined against the global storm index Dst for the whole 9‐year data set. Geomagnetic conditions were found to have only a small effect on autoscaling performance, with the most important identifiable cause of error being the truncation of automatic layer traces due to broadcast interference. Overall, the performance of the autoscaling algorithms was found to be acceptable, with the characteristics foF2, h′E, M(3000)F2, and MUF(3000)F2 within defined error bounds for more than 90% of the time and all characteristics within these bounds more than 80% of the time.

The effects of periodontal instrument handle design on hand muscle load and pinch force

In comparison with people in other occupations, dentists and dental hygienists are at increased risk of developing work-related musculoskeletal disorders, including carpal tunnel syndrome. An important risk factor in dental practice is forceful pinching, which occurs during dental scaling. Ergonomically designed dental instruments may help reduce the prevalence of MSDs among dental practitioners. In the authors' study, 24 dentists and dental hygienists used 10 custom-designed dental scaling instruments with different handle diameters and weights to perform a simulated scaling task. The authors recorded the muscle activity of two extensors and two flexors in the forearm with electromyography, while thumb pinch force was measured by pressure sensors. Handle designs of periodontal instruments had significant (P < .05) effects on hand muscle load and pinch force during a manual scaling task. The instrument with a large diameter (10 millimeters) and a light weight (15 grams) required the least amount of muscle load and pinch force. There was a limit to the effect of handle diameter, with diameters larger than 10 mm having no additional benefit; however, the study did not identify a limit to the effect of reducing the weight of the instrument, and therefore instruments lighter than 15 g may require even less pinch force. The results from this study can guide dentists and dental hygienists in selection of dental scaling instruments.