Question: when does the sa node begin electrical signaling
[{'answer': 'spontaneously', 'provenance': [{'wikipedia_id': '650897', 'title': 'Electrical conduction system of the heart', 'start_paragraph_id': 23, 'start_character': 48, 'end_paragraph_id': 23, 'end_character': 61, 'bleu_score': 1.0, 'section': 'Section::::ECG.:SA node: P wave.\n'}]}, {'answer': 'spontaneously generated', 'provenance': [{'wikipedia_id': '650897', 'title': 'Electrical conduction system of the heart', 'start_paragraph_id': 23, 'start_character': 48, 'end_paragraph_id': 23, 'end_character': 71, 'bleu_score': 1.0, 'section': 'Section::::ECG.:SA node: P wave.\n'}]}, {'provenance': [{'wikipedia_id': '650897', 'title': 'Electrical conduction system of the heart', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8253555650634923192}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '650897', 'title': 'Electrical conduction system of the heart', 'start_paragraph_id': 23, 'start_character': 0, 'end_paragraph_id': 23, 'end_character': 376, 'bleu_score': 0.9663744727315161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8253555650634923192}, 'section': 'Section::::ECG.:SA node: P wave.\n'}]}, {'provenance': [{'wikipedia_id': '11768704', 'title': 'Initial Detection Point (telephony)', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The IDP receives a message (IDP Message) initiated by the SSP (service switching point) and transmitted to the service control point SCP via the INAP protocol. The Service Switching Point (SSP) receives a message "(ISUP Message)" initiated by the Calling Party, this could be an IAM (Initial Address Message). The SSP evaluates the nature of the message, in the case of the IAM the called and calling party numbers. From this it determines whether it can route the call or whether it needs further instructions. In this case if the SSP does require further instructions it sends an IDP to a service control point SCP via an IN protocol. The protocol may be INAP but could be CAMEL, or bespoke INAP flavours such as Ericsson INAP, Nokia INAP, Siemens INAP', 'he IDP receives a message (IDP Message) initiated by the SSP (service switching point) and transmitted to the service control point SCP via the INAP protocol. The Service Switching Point (SSP) receives a message "(ISUP Message)" initiated by the Calling Party, this could be an IAM (Initial Address Message)']}}]}, {'provenance': [{'wikipedia_id': '22524356', 'title': 'SAE J1772', 'section': 'Section::::Signaling.:Proximity Pilot.\n', 'start_paragraph_id': 49, 'end_paragraph_id': 49, 'meta': {'evidence_span': ['Proximity Pilot: The Proximity pin, PP (also known as "plug present"), as shown in the SAE J1772 example pinout, describes the switch, S3, as being mechanically linked to the connector latch release actuator. During charging, the EVSE side connects the PP-PE loop via S3 and a 150\xa0Ω R6; when opening the release actuator a 330\xa0Ω R7 is added in the PP-PE loop on the EVSE side which gives a voltage shift on the line to allow the electric vehicle to initiate a controlled shut off prior to actual disconnection of the charge power pins. However many low power adapter cables do not offer that locking actuator state detection on the PP pin. In an updated standard due in 2012, SAE proposes to use power line communication, specifically IEEE 1901, between the vehicle, off-board charging station,', 'Proximity Pilot: The Proximity pin, PP (also known as "plug present"), as shown in the SAE J1772 example pinout, describes the switch, S3, as being mechanically linked to the connector latch release actuator. During charging, the EVSE side connects the PP']}}]}, {'provenance': [{'wikipedia_id': '650897', 'title': 'Electrical conduction system of the heart', 'section': 'Section::::ECG.:SA node: P wave.\n', 'start_paragraph_id': 23, 'end_paragraph_id': 23, 'meta': {'evidence_span': ["Under normal conditions, electrical activity is spontaneously generated by the SA node, the cardiac pacemaker. This electrical impulse is propagated throughout the right atrium, and through Bachmann's bundle to the left atrium, stimulating the myocardium of the atria to contract. The conduction of the electrical impulses throughout the atria is seen on the ECG as the P wave.", 'electrical activity is spontaneously generated by the SA node']}}]}, {'provenance': [{'wikipedia_id': '598570', 'title': 'Sinoatrial node', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ["The sinoatrial node (also known as the SA node or the sinus node) is a group of cells located in the wall of the right atrium of the heart. These cells have the ability to spontaneously produce an electrical impulse (action potential; see below for more details), that travels through the heart via the electrical conduction system (see figure 1) causing it to contract. In a healthy heart, the SA node continuously produces action potential, setting the rhythm of the heart and so is known as the heart's natural pacemaker. The rate of action potential production (and therefore the heart rate) is influenced by nerves that supply it.", 'he sinoatrial node (also known as the SA node or the sinus node) is a group of cells located in the wall of the right atrium of the heart. These cells have the ability to spontaneously produce an electrical impulse (action potential; see below', 'These cells have the ability to spontaneously produce an electrical impulse']}}]}]