UsingtabletcomputerslikeApple'siPadandSamsung'sGalaxyNotejustbeforebedcanleadtoapoornight'ssleep，accordingtoresearch.
MoreandmorepeoplearetakingtheirtabletcomputerstobedwiththemtosurftheInternet，checkFacebookoremailbeforeswitchingoffthelight.__1__
Thatisbecausethistypeoflightislikedaylight，convincingthebrainthatitisstilldaytime.
Bluelightsuppresses(抑制)theproductionofabrainchemicalcalledmelatonin，whichhelpsusfallasleep.__2__
Bycontrast，thelightwhichisorangeorredintonesdoesnotsuppressthemelatoninproduction，perhapsbecauseourbrainsrecognizeitasasignalthatthedayisending.
__3__Whethertheyaretelevisionscreens，computerscreensormobilephonescreens.
However，becausemobilephonesandtabletcomputersarebynatureportable，nottosayaddictive，morepeoplearetakingthemintothebedroom.__4__
ResearchersattheLightingResearchCentre，attheRensselaerPolytechnicInstituteinNewYork，arewarningthatlookingattabletcomputers'displaysformorethantwohours“leadstothesuppressionofournaturalmelatoninlevelsasthedevicesgiveoffopticalradiationatshortwavelengths”．__5__
A．Inotherwords，theygiveoffbluerlight.
B．Butresearchersarewarningthatthebluishlighttheirscreensgiveoffcanstopusersgettingagoodnight'ssleep.
C．Usersalsotendtoholdthemmuchclosertotheireyesthanacomputerortelevisionscreen.
D．Itisnotjustagoodnight'ssleepthatcouldbedamagedbytoomuchlatenightscreentime.
E．Neurologistshaveknownforyearsthatstaringatscreenslateintheeveningcandisruptsleep.
F．Thisisbecauseourbrainshaveevolvedtobewakefulduringdaylighthours.
G．Researchersknowthatpersistentdamagetosleeppatternscanleadtoanincreasedriskofobesity，andevenbreastcancer.
