JP2012005453A - Plant cultivation device, and method for cultivation of plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform radiation of light in plant cultivation.SOLUTION: The plant cultivation device 1 includes an illumination part 11, a photographing part 12, and a control part. The illumination part 11 includes a light source part 111, an optical fiber 112, and a scan mechanism 113. The light source part 111 includes a semiconductor laser. The photographing part 12 obtains an image of a cultivation object 91, and a light radiation range is determined based on the image. The scan mechanism 113 two-dimensionally scans light from the optical fiber 112. Under control by the control part, light is outputted from the semiconductor laser only while the radiation position is located within the radiation range. The radiation range is changed in accordance with growth of the cultivation object 91. Light is thus efficiently radiated to the cultivation object 91. Since the optical fiber 112 is used, effects of heat emitted from the light source 111 on the cultivation object 91 are reduced.

Description

  The present invention relates to a technique for cultivating plants by artificial lighting.

  In recent years, research on cultivating plants by artificial lighting has been carried out and put into practical use as a plant factory. In such plant cultivation, the cost required for lighting is important, and the use of light emitting diodes (LEDs) having a long life instead of light bulbs and fluorescent lamps has attracted attention. However, since LEDs are more expensive than light bulbs and fluorescent lamps, it is necessary to reduce the number of LEDs used.

  For example, in Patent Document 1, a bulk lens is provided in each of a plurality of LEDs (or semiconductor lasers (LDs)) that irradiate light to one plant. Thereby, the light from LED is irradiated to a plant efficiently. FIG. 9 of Patent Document 2 discloses a technique in which an LED unit is arranged so that light strikes only plants on the ridge, and the LED unit is moved by a moving unit. Further, the amount of light is changed by adjusting the height of the LED illumination unit. Patent Document 3 discloses a technology in which a straight tube type light source is provided with a substantially bowl-shaped reflector, and the reflector is deformed according to the size of the cultivation bench and the degree of growth of many plants. Non-Patent Document 1 mentions that light absorption efficiency by plants is enhanced by pulse irradiation of plants by LEDs and LDs.

  On the other hand, Patent Document 4 discloses a method for discriminating a lesion of a plant, withering, or a transition process to these states by observing laser-induced fluorescence emitted from the plant by laser light irradiation.

JP 2002-223636 A JP-A-2005-27521 JP 2008-125212 A JP 2002-214141 A

Masaaki Takatsuki, “Promotion of Science and Technology that Utilizes and Creates Light Resources (Toward a Sustainable“ Century of Light ”) Chapter 2“ Light that Contributes to a Rich Life ”, [online], Science and Technology / Academic Deliberation Society Resource Research Subcommittee, [Search May 24, 2010], Internet <http://www.mext.go.jp/b_menu/shingi/gijyutu/gijyutu3/toushin/07091111/004.htm>

  By the way, since a plant grows, when irradiating light with the method of patent document 1 and 2, it is necessary to irradiate light in a wide range in consideration of the growth of a plant. For this reason, the light use efficiency is reduced at the initial stage of plant growth. Also in patent document 3, since many plants are illuminated collectively, the utilization efficiency of light falls. Further, when an LED is used as a light source, light is diffused, so that it is not easy to efficiently use light.

  This invention is made | formed in view of the said subject, and aims at performing irradiation of the light in cultivation of a plant still more efficiently.

  Invention of Claim 1 is a plant cultivation apparatus, Comprising: The semiconductor laser and the light radiate | emitted from the said semiconductor laser are within the predetermined irradiation range containing the area | region where the chloroplast to be grown exists. An irradiation range limiting unit for guiding and an irradiation range changing unit for changing the irradiation range are provided.

  Invention of Claim 2 is the plant cultivation apparatus of Claim 1, Comprising: The scanning which the said irradiation range restriction | limiting part and the said irradiation range change part scan the light radiate | emitted from the said semiconductor laser two-dimensionally A mechanism, and a laser control unit that activates the semiconductor laser only while the irradiation position of the light is within the irradiation range.

  Invention of Claim 3 is the plant cultivation apparatus of Claim 2, Comprising: The imaging part and the chloroplast area | region detection part which detects the existence area | region of a chloroplast from the image acquired by the said imaging part And an irradiation range determining unit that determines the irradiation range from the existing region of the chloroplast.

  Invention of Claim 4 is a plant cultivation apparatus of Claim 3, Comprising: The lesioned part detection part which detects the lesioned part of the said cultivation object based on the image acquired by the said imaging part is further provided .

  Invention of Claim 5 is the plant cultivation apparatus of Claim 4, Comprising: The other semiconductor laser which radiate | emits blue light is further provided, The said scanning mechanism scans the said blue light two-dimensionally, The lesioned part detection unit detects the lesioned part based on an image acquired by the imaging unit while irradiating the cultivation target with light from the other semiconductor laser.

  Invention of Claim 6 is a plant cultivation apparatus of Claim 5, Comprising: The said laser control part deactivates the said semiconductor laser only while the irradiation position is located on the said lesion part, and said others The semiconductor laser is activated.

  Invention of Claim 7 is a plant cultivation apparatus of Claim 1, Comprising: The said irradiation range restriction | limiting part is provided with the lens arrange | positioned on the optical path from the said semiconductor laser to the said cultivation object, The said irradiation The range changing unit includes a lens moving mechanism that moves the lens along the optical axis.

  Invention of Claim 8 is the plant cultivation apparatus in any one of Claim 1 thru | or 7, Comprising: The said irradiation range restriction | limiting part injects the light radiate | emitted from the said semiconductor laser from one end, and the other end The optical fiber which radiates | emits from is provided.

  Invention of Claim 9 is a plant cultivation method, Comprising: The process of guide | inducing the light radiate | emitted from the semiconductor laser in the predetermined irradiation range containing the area | region where the chloroplast which is cultivation object exists, And a step of changing the irradiation range in accordance with the growth of the cultivation target.

  According to the present invention, light irradiation in plant cultivation can be performed efficiently.

  In the invention of claim 2, the irradiation range can be easily changed. In the invention of claim 3, the irradiation range can be automatically changed, and in the invention of claim 6, growth at the lesioned part can be suppressed.

  In the invention of claim 7, the limitation and change of the irradiation range are realized by a simple structure. In invention of Claim 8, the influence which the heat discharge | released from a semiconductor laser has on a cultivation object can be reduced.

It is a perspective view which shows a plant cultivation apparatus. It is a figure which shows a scanning mechanism. It is a block diagram which shows the function structure of a plant cultivation apparatus. It is a figure which shows a part of image acquired in the imaging part. It is a figure which shows the flow of operation | movement of a plant cultivation apparatus. It is a figure which shows the imaging part and filter switching part in 2nd Embodiment. It is a block diagram which shows the function structure of a plant cultivation apparatus. It is a figure which illustrates a lesioned part. It is a figure which shows a part of plant cultivation apparatus which concerns on 3rd Embodiment. It is a block diagram which shows the function structure of a plant cultivation apparatus. It is a figure which shows a part of flow of operation | movement of a plant cultivation apparatus. It is a figure which shows a part of plant cultivation apparatus.

  FIG. 1 is a perspective view showing a plant cultivation apparatus 1 according to the first embodiment of the present invention. The plant cultivation apparatus 1 includes a plurality of illumination units 11, an imaging unit 12, and a control unit (not shown). The illumination unit 11 and the imaging unit 12 are supported by a support member (not shown) in the cultivation space. The illumination unit 11 includes a light source unit 111, an optical fiber 112, and a scanning mechanism 113.

  The light source unit 111 houses a semiconductor laser that emits red light (hereinafter referred to as “first semiconductor laser”) and a semiconductor laser that emits blue light (hereinafter referred to as “second semiconductor laser”). . Red light and blue light emitted from the two semiconductor lasers are incident on one end of one optical fiber 112 via a multiplexer or the like in the light source unit 111 and emitted from the other end to the scanning mechanism 113. It is guided. The optical fiber 112 may be a bundle of two fibers, and red light and blue light may be incident on the two fibers, respectively.

  The wavelength of the light emitted from the first semiconductor laser is preferably 630 nm or more and 680 nm or less, and the wavelength of the light emitted from the second semiconductor laser is 500 nm or less, practically 400 nm or more. The width of the light emitting layer of these semiconductor lasers is 2 μm or more and 100 μm or less. Thereby, the below-mentioned light scanning can be easily performed.

  FIG. 2 is a perspective view showing the internal structure of the scanning mechanism 113. The scanning mechanism 113 includes a pair of galvanometer mirrors 21 and 22 extending perpendicularly to each other. The light emitted from the tip of the optical fiber 112 is scanned as the galvanometer mirrors 21 and 22 rotate and vibrate about the rotation axis. The two galvanometer mirrors 21 and 22 scan the irradiation position of the light on the cultivation object 91 that is a plant in two dimensions. The tip of the optical fiber 112 is formed into a spherical surface, and red light and blue light are emitted in a substantially parallel light state. The red light and the blue light are similarly scanned two-dimensionally by the scanning mechanism 113, and the irradiation positions of these lights coincide.

  The imaging unit 12 has a monochrome two-dimensional CCD as an imaging element. A filter that transmits green light is attached to the image sensor. In FIG. 1, the image pickup unit 12 picks up images of four cultivation targets 91 on the medium unit 92 in a lump. Each of the four illumination parts 11 irradiates one cultivation object 91 with light.

  FIG. 3 is a block diagram showing a functional configuration of the plant cultivation apparatus 1. The control unit 13 includes a laser control unit 131, an irradiation range determination unit 132, and a chloroplast region detection unit 133. The control unit 13 has a structure in which a dedicated hardware device is added to a general computer system. When the CPU executes arithmetic processing according to a program, each functional configuration shown in FIG. Realized.

  The laser control unit 131 individually controls ON / OFF of the first semiconductor laser 31 and the second semiconductor laser 32 in the light source unit 111 shown in FIG. The chloroplast region detection unit 133 detects a region where the chloroplast of the cultivation object 91 exists based on the image from the imaging unit 12. The irradiation range determination unit 132 determines the irradiation range of red light and blue light based on the detection result by the chloroplast region detection unit 133.

  FIG. 4 is a diagram illustrating a part of an image acquired by the imaging unit 12, and FIG. 5 is a diagram illustrating a flow of operation of the plant cultivation apparatus 1. Note that step S21 in FIG. 5 is executed only in the second embodiment described later. First, the white illumination in the room where the plant cultivation apparatus 1 is provided is temporarily turned on, and an image of the cultivation object 91 is acquired by the imaging unit 12 (step S11). Then, the chloroplast region detection unit 133 acquires the green portion in the image, that is, the bright portion in the image acquired through the filter, as the chloroplast existence region (step S12). The irradiation range determining unit 132 determines a circular, elliptical, rectangular, or polygonal region surrounding the chloroplast existing region as the light irradiation range (step S13). In FIG. 4, the determined irradiation range is indicated by a broken line denoted by reference numeral 81.

  When the irradiation range 81 is determined, the scanning mechanism 113 is driven, and the irradiation position of the light from the semiconductor laser is repeatedly scanned two-dimensionally. In FIG. 4, a broken line and a solid line extending in the horizontal direction indicate the scanning locus of the irradiation position. For example, the irradiation position is sub-scanned from top to bottom each time main scanning from left to right is repeated. The first semiconductor laser 31 and the second semiconductor laser 32 are activated and emit light only while the irradiation position is within the irradiation range 81 (step S14). Thereby, light is irradiated in the irradiation range 81 as shown by the solid line extending in the horizontal direction.

  The ratio of red light to blue light is a unit of photon flux density and is preferably 10: 1 to 5: 1. The first semiconductor laser 31 and the second semiconductor laser 32 may emit light continuously or may emit pulses. In the case of pulse light emission, the two-dimensional scanning cycle and the pulse light emission cycle are adjusted so as not to be synchronized. As a result, light is uniformly irradiated within the irradiation range 81. Depending on the type of plant, only red light may be irradiated.

  In the actual operation of the plant cultivation apparatus 1, steps S11 to S13 in FIG. 5 are performed at regular intervals (for example, every day), and step S14 is continued while steps S11 to S13 are not performed. Done.

  As described above, the plant cultivation device 1 can irradiate light only within the predetermined irradiation range 81. When the cultivation target 91 is separated, a region where light is not irradiated is provided in a region where the lighting between the cultivation targets 91 is unnecessary. Moreover, the irradiation range 81 can be easily changed and can be appropriately matched with the shape of the cultivation object 91. In addition, light from the semiconductor laser is guided into the irradiation area 81 without being substantially blocked. As a result, the cultivation object 91 can be efficiently irradiated with light.

  Since the irradiation range 81 is determined based on the image from the imaging unit 12, the irradiation range 81 can be automatically expanded in accordance with the growth of the cultivation target 91. Furthermore, when attention is paid to one point on the cultivation target 91, since a high-intensity laser beam is intermittently irradiated, further energy reduction is realized. Since the light source unit 111 and the scanning mechanism 113 are connected by the optical fiber 112, the light source unit 111 can be arranged away from the cultivation target 91, and the influence that the heat emitted from the semiconductor laser has on the cultivation target 91. It can be easily reduced.

  The operational effects according to the first embodiment are the same in the following second embodiment.

  The scanning mechanism 113 may be a combination of a galvanometer mirror and a polygon mirror. Furthermore, the scanning of light may be performed by an electro-optic element having a micro electro mechanical system (MEMS) mirror or an electro-optic crystal. A semiconductor laser that emits green light or a laser that emits light of other wavelengths may be added. A plurality of cultivation objects 91 may be irradiated with light by one lighting unit 11. The same applies to other embodiments described below.

  In the plant cultivation apparatus 1, the light irradiation range is determined by the optical fiber 112, the scanning mechanism 113, and the laser control unit 131. That is, these structures function as an irradiation range limiting unit that limits the irradiation range. Further, since the irradiation range is changed by ON / OFF control of the semiconductor laser by the laser control unit 131, the laser control unit 131 functions as an irradiation range changing unit. However, since the irradiation range can also be changed by changing the scanning range by the scanning mechanism 113, the scanning mechanism 113 can also function as an irradiation range changing unit. The same applies to the second embodiment.

  FIG. 6 is a diagram illustrating a configuration of the imaging unit 12 and the vicinity thereof in the plant cultivation apparatus 1 according to the second embodiment. A rotary filter switching unit 14 is provided below the imaging unit 12. Further, as shown in FIG. 7, the control unit 13 is further provided with a lesion part detection unit 134. The other structure of the plant cultivation apparatus 1 is the same as that of 1st Embodiment, and attaches | subjects the same code | symbol.

  The filter switching unit 14 includes a disk part 142 to which a plurality of filters 141 are attached, and a motor 143 that rotates the disk part 142. As the motor 143 rotates, the filter 141 disposed in front of the imaging unit 12 is switched. The filter 141 includes a bandpass filter that transmits light having a wavelength of 680 nm to 690 nm (hereinafter referred to as “first wavelength band”) and a wavelength of 735 nm to 745 nm (hereinafter referred to as “second wavelength band”). ) At least a band pass filter that transmits light.

  When an image of the cultivation target 91 is acquired in the second embodiment (FIG. 5: Step S11), first, the band switching filter 141 in the first wavelength band is moved in front of the imaging unit 12 by the filter switching unit 14. The second semiconductor laser 32 is continuously turned on, and the irradiation position is scanned two-dimensionally by the scanning mechanism 113. Thereby, the thing of a 1st wavelength band is acquired as a 1st image among the laser induced fluorescence emitted from the cultivation object 91. FIG. Next, the band switching filter 141 in the second wavelength band is disposed in front of the imaging unit 12 by the filter switching unit 14, the second semiconductor laser 32 is continuously turned on, and the irradiation position is scanned two-dimensionally by the scanning mechanism 113. . Thereby, the thing of a 2nd wavelength band is acquired as a 2nd image among the laser induced fluorescence of the cultivation object 91. FIG.

  The chloroplast region detection unit 133 and the lesion detection unit 134 detect the chloroplast existing region and the lesion or dead region of the cultivated object 91 based on the first image and the second image (step) S12, S21). Here, for example, a region where a pixel value larger than a predetermined threshold value appears in at least one of the first image and the second image is detected as a chloroplast existing region. In addition, a method disclosed in Japanese Patent Laid-Open No. 2002-214141 (Patent Document 4) is used to detect a lesion area. Specifically, by comparing the first image and the second image, a region where (fluorescence intensity in the second wavelength band / fluorescence intensity in the first wavelength band) is 1.0 or less is detected as a lesion area. Is done. Of course, a lesion path may be detected by providing the filter switching unit 14 with a bandpass filter of another wavelength band. As shown in Patent Document 4, a wavelength band of 520 nm or more and 540 nm or less of laser induced fluorescence may be used.

  Detection of a lesioned part (more precisely, detection of a region of a lesioned part in an image) may be performed by a simpler method. For example, an RGB filter may be provided in the filter switching unit 14 or a color camera may be separately provided to obtain a color image of the cultivation target 91 under white illumination, and a lesioned part may be detected from the color of the cultivation target 91. .

  When the chloroplast existing region and the lesioned region are detected, the irradiation range determining unit 132 causes the region including the chloroplast existing region to have strong red light and weak blue light as in the first embodiment. The irradiation range (hereinafter referred to as “growth irradiation range”) is determined, and the region of the lesion area is determined as the irradiation range of only strong blue light (hereinafter referred to as “suppression range”) (step S13). In FIG. 8, the growth irradiation range is illustrated by a broken line denoted by reference numeral 81, and the suppression range is illustrated by a region denoted by parallel oblique lines denoted by reference numeral 82.

  Thereafter, the first semiconductor laser 31 and the second semiconductor laser 32 are activated only while the irradiation position is within the growth irradiation range 81 by the laser control unit 131 while the irradiation position is scanned two-dimensionally by the scanning mechanism 113. As a result, strong red light and weak blue light are emitted, and the first semiconductor laser 31 is deactivated and the second semiconductor laser 32 is activated and strong blue only while the irradiation position is within the suppression irradiation range 82. Light is emitted (step S14). Thereby, the growth in the lesioned part is suppressed while growing the cultivation object 91. As a result, the enlargement of the lesion is suppressed.

  Also in the second embodiment, since the light from the semiconductor laser is guided into the growth irradiation range 81 without being blocked, the cultivation target 91 can be cultivated efficiently. Moreover, the growth irradiation range 81 and the suppression irradiation range 82 can be automatically changed according to the growth of the cultivation object 91, and the work can be reduced. In the second embodiment, the second semiconductor laser 32 is used for all of detection of the chloroplast existing area, detection of the lesion area, growth, and suppression of growth in the lesion area.

  FIG. 9 is a diagram illustrating a part of the plant cultivation apparatus 1 according to the third embodiment. The configuration shown in FIG. 9 is provided in place of the scanning mechanism 113 shown in FIG. 1 and includes a lens 151 and a lens moving mechanism 152 that moves the lens 151 up and down. FIG. 10 is a block diagram illustrating a configuration connected to the control unit 13 and the control unit 13. In the light source unit 111 of FIG. 1, only the semiconductor laser 31 that emits red light is provided. The optical fiber 112 of each illumination unit 11 is a single fiber. As shown in FIG. 9, the light emitted from the optical fiber 112 reaches the lens 151 while diverging, and is guided into the irradiation range 81 surrounding the cultivation target 91 by the lens 151 having positive power. Light from the optical fiber 112 is guided into the irradiation range 81 without being blocked. The other structure of the plant cultivation apparatus 1 is the same as that of the first embodiment, and the same structure will be described below with the same reference numerals. Semiconductor lasers that emit light of other wavelengths may be combined.

  In the plant cultivation device 1, as in the first embodiment, the image of the cultivation object 91 is acquired by the imaging unit 12 (FIG. 5: step S <b> 11), and the chloroplast region detection unit is based on the acquired image. 133 detects the chloroplast existing area, and the irradiation range determination unit 132 determines a circular irradiation range surrounding the chloroplast existing area (steps S12 and S13). Thereafter, step S31 shown in FIG. 11 is executed, and the lens 151 is moved up and down along the optical axis by the lens moving mechanism 152 to change the irradiation range 81.

  Steps S11 to S14 are performed for a certain period, for example, every day. Thereby, as shown in FIG. 12, the lens 151 moves according to growth of the cultivation object 91, and the irradiation range 81 is expanded. As a result, the work can be reduced as in the first embodiment. Further, the light from the semiconductor laser 31 is irradiated within the irradiation range 81 without being blocked, so that illumination can be performed efficiently. The semiconductor laser 31 may be pulsed, thereby further reducing power consumption.

  In the third embodiment, the optical fiber 112 and the lens 151 function as an irradiation range limiting unit that limits the irradiation range of light, and the lens moving mechanism 152 functions as an irradiation range changing unit that changes the irradiation range. In this way, the irradiation range is limited and changed with a simple structure. Also in the third embodiment, by using the optical fiber 112, the influence of the heat emitted from the semiconductor laser on the cultivation target 91 can be easily reduced.

  In addition to the lens 151, another lens may be provided as the irradiation range limiting unit. The lens includes a mirror lens that is an equivalent mirror. As the irradiation range changing unit, a mechanism for moving a plurality of lenses along the optical axis or a mechanism for moving a mirror may be provided. Furthermore, as long as the light from the semiconductor laser can be guided into the irradiation range 81 without being substantially blocked, another optical element may be used as the irradiation range limiting unit or the irradiation range changing unit. The end of the optical fiber 112 itself may function as an irradiation range limiting unit, and a mechanism for moving the end up and down may be provided as the irradiation range changing unit.

  The lens 151 may be disposed at another position as long as it is disposed on the optical path from the semiconductor laser 31 to the cultivation target 91. For example, the optical fiber 112 may be omitted, and the cultivation target 91 may be irradiated with light from the semiconductor laser 31 via a plurality of lenses and mirrors including the lens 151.

  The configuration described in each of the above embodiments may be adopted in other embodiments as long as there is no contradiction.

  The present invention can be used for cultivation of various plants such as vegetables, ornamental plants, and resource plants. A plant is not limited to what grows on the ground, but may grow in water as long as it contains chlorophyll.

DESCRIPTION OF SYMBOLS 1 Plant cultivation apparatus 12 Image pick-up part 31 1st semiconductor laser 32 2nd semiconductor laser 81 Irradiation range 82 Lesion part 91 Cultivation object 112 Optical fiber 113 Scan mechanism 131 Laser control part 132 Irradiation range determination part 133 Chloroplast area detection part 134 Lesion Part detection part 151 lens 152 lens moving mechanism S11-S14, S21, S31 Step

Claims (9)

A plant cultivation device,
A semiconductor laser;
An irradiation range limiting unit that guides light emitted from the semiconductor laser into a predetermined irradiation range including a region where chloroplasts to be cultivated exist,
An irradiation range changing unit for changing the irradiation range;
A plant cultivation apparatus comprising: The plant cultivation apparatus according to claim 1,
The irradiation range restriction unit and the irradiation range change unit,
A scanning mechanism for two-dimensionally scanning light emitted from the semiconductor laser;
A laser control unit that activates the semiconductor laser only while the irradiation position of the light is within the irradiation range;
A plant cultivation apparatus comprising: The plant cultivation apparatus according to claim 2,
An imaging unit;
A chloroplast region detecting unit for detecting a chloroplast existing region from the image acquired by the imaging unit;
An irradiation range determining unit for determining the irradiation range from the existence region of the chloroplast;
The plant cultivation apparatus further comprising: The plant cultivation device according to claim 3,
A plant cultivation apparatus, further comprising a lesion part detection unit that detects a lesion part of the cultivation target based on an image acquired by the imaging unit. The plant cultivation apparatus according to claim 4,
It further includes another semiconductor laser that emits blue light,
The scanning mechanism scans the blue light in two dimensions;
The plant cultivation apparatus, wherein the lesion detection unit detects the lesion based on an image acquired by the imaging unit while irradiating the cultivation target with light from the other semiconductor laser. The plant cultivation device according to claim 5,
The plant cultivation apparatus, wherein the laser control unit deactivates the semiconductor laser and activates the other semiconductor laser only while an irradiation position is located on the lesioned part. The plant cultivation apparatus according to claim 1,
The irradiation range restriction unit includes a lens disposed on an optical path from the semiconductor laser to the cultivation target,
The plant cultivation apparatus, wherein the irradiation range changing unit includes a lens moving mechanism that moves the lens along an optical axis. A plant cultivation apparatus according to any one of claims 1 to 7,
The plant cultivation device, wherein the irradiation range limiting unit includes an optical fiber from which light emitted from the semiconductor laser enters from one end and exits from the other end. A plant cultivation method,
Guiding the light emitted from the semiconductor laser into a predetermined irradiation range including a region where the chloroplasts to be cultivated exist; and
Changing the irradiation range according to the growth of the cultivation target;
A plant cultivation method comprising:

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