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<title id="title">Two processes shape sleep timing</title>
<desc id="desc">A looping circadian clock synchronized by light and darkness converges with a separate homeostatic sleep-need panel that builds while awake and lessens during sleep. Both contribute to sleep and wakefulness.</desc>
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<text x="40" y="56" font-size="34" font-weight="600" fill="#1d1d1f" text-anchor="start">Two processes shape sleep timing</text>
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<circle cx="230" cy="285" r="130" fill="#ffffff" stroke="#054a6b" stroke-width="3"/><path d="M230 184A101 101 0 1 1 131 308" fill="none" stroke="#054a6b" stroke-width="5"/><path d="M 131 308 L 144 285" fill="none" stroke="#054a6b" stroke-width="3" marker-end="url(#arrow)"/><text x="230" y="266" font-size="31" font-weight="600" fill="#054a6b" text-anchor="middle">Circadian</text>
<text x="230" y="307" font-size="31" font-weight="600" fill="#054a6b" text-anchor="middle">timing</text><text x="40" y="477" font-size="25" font-weight="400" fill="#1d1d1f" text-anchor="start">Light and darkness help</text>
<text x="40" y="512" font-size="25" font-weight="400" fill="#1d1d1f" text-anchor="start">synchronize the body clock.</text><text x="568" y="196" font-size="27" font-weight="600" fill="#1d1d1f" text-anchor="start">Homeostatic sleep need</text><text x="568" y="247" font-size="25" font-weight="400" fill="#1d1d1f" text-anchor="start">Builds with time awake.</text>
<text x="568" y="282" font-size="25" font-weight="400" fill="#1d1d1f" text-anchor="start">Lessens during sleep.</text>
<text x="568" y="317" font-size="25" font-weight="400" fill="#1d1d1f" text-anchor="start">A different process</text>
<text x="568" y="352" font-size="25" font-weight="400" fill="#1d1d1f" text-anchor="start">from the body clock.</text><path d="M 361 331 L 410 561" fill="none" stroke="#6e6e73" stroke-width="3" marker-end="url(#arrow)"/><path d="M 655 422 L 553 561" fill="none" stroke="#6e6e73" stroke-width="3" marker-end="url(#arrow)"/><text x="480" y="625" font-size="29" font-weight="600" fill="#0a5c22" text-anchor="middle">Sleep and wakefulness</text>
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<text x="40" y="722" font-size="22" font-weight="400" fill="#6e6e73" text-anchor="start">Conceptual diagram • not measured data</text>
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