CBS Boston /YouTubeA mom charged with reckless endangerment and involuntary manslaughter in connection with the death of her 3-year-old had left her son with no adult supervision and spent the evening drinking in a bar despite being aware he was unwell, prosecutors say.Jennifer Prudencio, 25, of Chelsea, Massachusetts, has pleaded not guilty to the charges filed following the death of her son, Yael Guardado Prudencio, on Sunday. She was ordered held on $100,000 bail at her arraignment Wednesday.