Spot size

CPEG therefore undertook to recreate the weight-for-age curves for children 10–19 years of age, using a statistical method identical to that used by WHO, and including the majority of the data points in the WHO curves. Following discussions between the original collaborative group and CPEG, a consensus was achieved in March 2014, whereby two sets of growth charts would be released, both including the new weight-for-age curves developed by CPEG and differing only in the percentiles plotted:

In 2010, the WHO Growth Charts for Canada were released and were recommended as the standard growth charts for all Canadian children, to replace the CDC growths in use since 2000. The formatting of the 2010 charts was the result of a collaborative statement by the Dietitians of Canada, the Canadian Paediatric Society, the College of Family Physicians of Canada, and the Community Health Nurses of Canada.

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There is also an option for those wanting to use these CPEG macros in either a clinical or research context, but who are uncomfortable with a statistical package. The Canadian Pediatric Endocrine Group has created on-line applications (Zapps™) running these macros on an R server (a/k/a Shiny), available here on their website.

We offer diffraction-limited collimation beam expanders for a wide range of input beams, and adjustable beam expanders which improve the divergence angle of laser beams. Our beam expanders can provide magnification from 1.5 times to 10 times, and we produce optics and coatings customized to fit specific application needs.

Beam Expanders are optical devices that increase the diameter of the input beam to produce a larger output. Used with collimated positive focal lengths. Refers to lenses that converge light rays to a focal point. In beam expanders, lenses with positive focal lengths are used to manipulate the beam path effectively, either in Keplerian or Galilean telescope configurations. They have important applications in remote sensing, interferometry, and laser scanning.

A beam expander is often an optical telescope, formed of two lenses. The two most widely used configurations include the so-called Keplerian telescope and the Galilean telescope.

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In high-power laser systems, beam expanders are used to increase the beam area without significantly affecting the total laser energy. This results in a reduction of the laser power density which reduce the risk of damaging the coatings and optical materials of optical components.

Laser beam

See also our Anthropometric Calculators (tab above) for determining percentiles and Z-scores for the WHO Growth Charts for Canada, in addition to the CDC Growth Charts and a number of common syndromes.

Dr. Atul Sharma, MD, MSc, FRCPC, Assistant Professor, Department of Pediatrics and Child Health, University of Manitoba, has developed a web-based height-, weight- and BMI-plotting app for children from birth to age 19 years, using the WHO Growth Charts for Canada, 2014 revision. The app can be used to make images of plots for presentations (see screenshot below).

For those who prefer to create growth charts by uploading anthropometric data in spreadsheet (csv) format, the Canadian Pediatric Endocrine Group has also created Shiny plotters for this purpose:

Beam expander

Our pre-engineered lenses give our customers the option to choose from a variety of preliminary designs based on what suits their application best. But you aren’t limited to in-stock options.  Just tell us your application requirements (dimensions, wavelength range, field of view, etc.) and our team of expert engineers will optimize our preliminary designs to meet your exact needs. This will save you the hassle of fully designing a product from scratch and help reduce or eliminate design fees!

Gaussianbeamcalculator

The BCCH Anthropometric Calculators can calculate Z-scores and centiles for height/length, weight, head circumference, body-mass index, waist circumference, waist/height ratio, BMI, blood pressure (2004 NHBLI and 2017 AAP), skinfold thickness, arm circumference, height velocity, target (midparental) height, and predicted adult height for typically growing children and for children with selected syndromes, based on published norms.

You can also choose to plot selected growth parameters (such as height, weight, body-mass index and head circumference) for children with a number of syndromes (Turner, Down, Noonan, Prader–Willi and Russell–Silver).

Our in-stock selection of beam expanders includes both fixed- and variable-magnification high-quality beam expanders for use in the UV, visible, and infrared spectral range. Variable-magnification beam expanders provide divergence adjustability.  Our zoom beam expanders work with high power laser and in demanding conditions, and provide high transmittance with less energy loss.

How to make abeam expander

A beam expander can be used in reverse to decrease a laser beam diameter, but the divergence will be significantly increased. If a beam expander is used to reduce a beam by half, the divergence will be doubled.

Beam Expanders not only increase the diameter of a collimated laser beam, they also decrease beam divergence. Input Beam Diameter is the diameter of the laser beam entering the beam expander. This parameter is crucial as it determines the necessary specifications for the beam expander to achieve the desired output beam diameter. The entire system does not have a focal length, i.e., both the input beam and output beam are collimated in a beam expander system. For many applications, the input laser beam has spatially varying intensity “noise” and a spatial filter is added into the beam expander system for producing a clean laser beam.

In a laser ranging system, a beam expander is used to minimize laser divergence, resulting in a smaller collimated beam at a long distance.

These workbooks are free and do not contain macros. They may be used online or downloaded and saved to your hard drive or mobile device.

Beamdivergence calculator

A number of individuals and professional organizations, most notably the Canadian Pediatric Endocrine Group (CPEG), raised three concerns about the new WHO charts. In particular, CPEG felt that the loss of weight-for-age curves from ages 10–19 years in favour of a sole emphasis on the calculation of body-mass index (BMI) made the charts less useful for short-term clinical evaluation of weight gain or loss in growing children. Secondly, the inclusion of curves for the 0.1st and 99.9th centiles in the 2010 charts raised the possibility of some physicians considering these extremes as the “normal range”, possibly delaying referral of children until they reached one of these extremes. Finally, the loss of the number of intermediate-centile (10th, 25th, 75th and 90th) curves on the 2010 charts made it potentially more difficult for clinicians to identify children who were “crossing centiles”.

A number of resources are available on this website and that of the Canadian Pediatric Endocrine Group to assist clinicians in calculating Z-scores and centiles for anthropometric data for typically growing children, children with syndromes, and premature infants.

Keplerianbeam expander

Our AnthroCalc app is available on Google Play and on the App Store. The AnthroCalc app calculates centiles and Z-scores for height/length, weight, weight-for-length, body-mass index, waist circumference, head circumference, target (midparental) height, predicted adult height, and height velocity for typically growing children (using WHO or CDC references); for blood pressure (using NIH 2004 or AAP 2017 references); for children with a number of syndromes (Turner, Down, Prader–Willi, Russell–Silver and Noonan); and for preterm infants (Fenton, INTERGROWTH-21st).

A Galilean telescope is formed of one plano-convex and one plano-concave lens. These lenses are also arranged so that the distance between them is equal to their focal length; although here the focal length of one of the lenses is negative.  The distance between the lenses can be shorter than for a Keplerian beam expander, leading to a more compact system. A Galilean design beam expander does not invert the image.

Our GrowthPlot app is available on Google Play and on the App Store. The GrowthPlot app plots length, weight, head circumference and weight-for-length for children (0–24 months of age for WHO, 0–36 months for CDC); and it plots height, weight and body-mass index for children (2–19 years of age for WHO, 2–20 years for CDC). Plots for WHO are made using the WHO Growth Charts for Canada, March 2014 revision, and plots for CDC are made using the 2000 CDC Growth Charts.

We also have available a number of Microsoft® Excel workbook–based batch calculators, to be used in conjunction with the above calculator workbooks. Please note that these workbooks contains macros, which will have to be enabled for them to work. For each batch calculator, there is a worksheet in its workbook with instructions for use. Please also note that these workbook files and the associated anthropometric calculator files must be placed in the same folder on your computer's hard drive or network drive. There are problems reported using this with Macs that we have been unable to resolve. Currently available:

BC Children’s Hospital has now printed and integrated the use of the Set 2 consensus charts. We encourage all clinicians and public-health clinics seeing children in BC to switch to the revised WHO Growth Charts for Canada, and measures are underway through the BC Ministry of Health to ensure that this occurs on the public-health side as well.

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Please contact us at 732-321-6915 or contact a representative to learn more about product availability, lead time, pricing and capabilities.

Beam expanders are used in many applications such as laser ranging, laser illumination, interferometry, etc.  In systems with a long beam path, they are used to keep the beam collimated. They may be used to change the focus spot size for a particular focusing lens.

Beam ExpanderThorlabs

Provincial Health Services Authority (PHSA) improves the health of British Columbians by seeking province-wide solutions to specialized health care needs in collaboration with BC health authorities and other partners.

One should also be aware that a Keplerian beam expander will invert and revert the image. A third lens can be used to correct this if desired.

Also take a look at the browser-based Growth Chart Plotter App (tab above) for plotting heights and weights for boys and girls ages 2 to 19 years, ideal for making growth charts for PowerPoint presentations.‎

English and French versions of both sets of growth charts are freely available for download at www.whogrowthcharts.ca, as well as instructions for how they should be printed. For those individuals and electronic health-records companies wishing access to the LMS data used to plot the charts, these are available on the CPEG website here.

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A beam expander is characterized by its beam expansion ratios, also sometimes referred to as the magnifying power, power, or magnification. This ratio is equal to the ratio of the focal lengths of output and input lenses.  If a laser beam is expanded by a ratio of R, the divergence can be multiplied by the inverse (1/R). For instance, if the beam expansion ratio is 3, the output beam will have only 1/3 the divergence of the input beam.

The Keplerian telescope may be the easiest beam expander one can build. For this configuration, two plano-convex (convergent) lenses are arranged so that the distance between them is equal to the sum of their focal lengths.  The focal point of the combined system will be in the gap between the lenses. Since high pulse energy density at this point may cause arcing, we do not recommend the use of Keplerian beam expanders for high energy lasers.   However, Keplerian-design beam expanders are a good choice for laser applications if spatial filtering is involved. The focus point is an appropriate place to position the spatial filter.