Birds that are literally half-asleep—with one brain hemisphere alert and the other sleeping—control which side of the brain remains awake, according to a new study of sleeping ducks.
Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemisphere’s eye stays open and alert. Birds also can sleep with both hemispheres resting at once.
Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemisphere’s eye stays open and alert. Birds also can sleep with both hemispheres resting at once.
Decades of studies of bird flocks led researchers to predict extra al
A. the phenomenon of birds dozing in pairs is widespread
B. birds prefer to sleep in pairs for the sake of security
C. even an imagined companion gives the bird a sense of security
D. a single pet bird enjoys seeing its own reflection in the mirror
男性，46岁。右上腹疼痛半年，加重伴上腹部包块1个月。半年前无明显诱因出现右上腹钝痛，为持续性，有时向右肩背部放射。近1个月来，右上腹痛加重，自觉右上腹饱满，有包块，伴腹胀、食欲缺乏、恶心，无呕吐、腹泻，偶有发热（体温最高38.1℃）。患者发病来，大小便正常，体重下降约5公斤。既往有乙型肝炎病史15年，否认疫区接触史，无烟酒嗜好，无药物过敏史，家族史中无遗传性疾病及类似疾病史。查体：T36.7℃、P78次/分，R18次/分，BP110/70mmHg，发育正常，营养一般，神清合作，全身皮肤无黄染，巩膜轻度黄染，双锁骨上窝未及肿大淋巴结，心肺（-）。腹平软，右上腹饱满，无腹壁静脉曲张，右上腹压痛，无肌紧张，肝脏肿大肋下5cm，边缘钝，质韧，有触痛，脾未及，腹叩鼓音，无移动性浊音，肝上界叩诊在第五肋间，肝区叩痛，肠鸣音8次/分，肛门指诊未及异常。
提示：血常规：RBC4.5×1012/L，Hb120g/L，WBC5.6×109/L；AFP1000ng/ml；乙肝两对半：HbsAg（+），Anti-HBs（-），HBeAg（-），Anti-HBe（+），Anti-HBc（+）；肝功能：ALB35.5g/L，ALT84IU/L，AST78IU/L，TBIL30μmol/L，DBIL10μmol/L，ALP188IU/L，GGT64IU/L。B超：肝右叶实质性占位性病变，直径约8cm，肝内外胆管不扩张；CT：肝右叶8cm×7cm边缘较模糊的低密度占位性病变，脾脏不大；纤维胃镜未发现食管静脉明显曲张。目前已明确的诊断是（）。| Six years later, in an about-face, the
FBI admits that federal agents fired tear gas canisters capable of causing a
fire at the Branch Davidian compound near Waco, Texas in 1993. But the law
enforcement official said the firing came several hours before the structure
burst into flames, killing 80 people including the Davidians’ leader, David
Koresh. "In looking into this, we’ve come across information that shows some canisters that can be deemed pyrotechnic in nature were fired—hours before the fire started," the official said. "Devices were fired at the bunker, not at the main structure where the Davidians were camped out." The Federal Bureau of Investigation maintains it did not start what turned to be a series of fiery bursts of flames that ended a 51-day standoff between branch members and the federal government. "This do A. the canisters were fired at the main structure B. the canisters were fired hours before the fire started C. federal agents fired tear gas canisters capable of causing a fire D. other tear gas canisters that were not flammable or potentially explosive were also used 我来回答: 提交
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