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Passage Two Our brains could be hard-wired to be male or female long before we begin to grow testes(丸)or ovaries(卵巢)in the womb. This discovery might explain why some people feel trapped in a body that’s the wrong sex, and could also lead to tests that reveal the true "brain sex" of babies born with ambiguous genitalia(生殖器). Till now, the orthodoxy among developmental biologists has been that embryos develop ovaries and become female unless a gene called SRY on the Y chromosome is switched on. If this gene is active, it makes testes develop instead. This switch is seen as the key event in determining whether a baby is a girl or a boy. Only after the gonads(性腺) form and flood the body with the appropriate hormones, the theory goes, is the sex of our minds and bodies determined. But in a study of mice, a team at the University of California, Los Angeles, has now found that males and females show differences in the expression of no fewer than 50 genes well before SRY switches on. "It’s the first discovery of genes differentially expressed in the brain, "says Eric Vilain, who led the UCLA team. "They may have an impact on the hard-wired development of the brain in terms of sexual differentiation independent of gonadal induction." Vilain is presenting details of seven of the 50 genes to the annual meeting of the American Society of Human Genetics in Baltimore this week. Three of these genes are dominant in females and four are dominant in males. The next step for Vilain and his team will be to show that the genes in question really do influence brain sexuality—and not just in mice. This is likely to be a much tougher proposition than merely showing there are differences in expression. But if the findings are confirmed, they could one day yield blood tests that allow doctors to establish the brain sex of babies born with genitalia that share features of both sexes. At present doctors and parents have to guess which gender to assign for surgical "correction". Which of the following word is closer to the word "hard-wired" in the first paragraph
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Outline: A. Describe what the girl in the picture is doing; B. Why is the girl in the picture sitting on the baby C. What does the picture imply
在建立下一个连接请求时，为了实现负载平衡，边界路由器会将虚拟地址映射为一个未曾映射过的内部地址或者是使用次数最少的内部地址。阅读以下说明，回答下面问题。 设有A，B，C，D四台主机都处在同一个物理网络中，A主机的IP地址是202.155.12.112，B主机的IP地址是202.155.12.120，C主机的IP地址是202.155.12.222，D主机的IP地址是202. 155.12.176。共同的子网掩码是255.255.255.224。 【问题3】 若要使主机A，B，C，D在这个网上都能直接相互通信，可采取什么办法
Passage Two Our brains could be hard-wired to be male or female long before we begin to grow testes(丸)or ovaries(卵巢)in the womb. This discovery might explain why some people feel trapped in a body that’s the wrong sex, and could also lead to tests that reveal the true "brain sex" of babies born with ambiguous genitalia(生殖器). Till now, the orthodoxy among developmental biologists has been that embryos develop ovaries and become female unless a gene called SRY on the Y chromosome is switched on. If this gene is active, it makes testes develop instead. This switch is seen as the key event in determining whether a baby is a girl or a boy. Only after the gonads(性腺) form and flood the body with the appropriate hormones, the theory goes, is the sex of our minds and bodies determined. But in a study of mice, a team at the University of California, Los Angeles, has now found that males and females show differences in the expression of no fewer than 50 genes well before SRY switches on. "It’s the first discovery of genes differentially expressed in the brain, "says Eric Vilain, who led the UCLA team. "They may have an impact on the hard-wired development of the brain in terms of sexual differentiation independent of gonadal induction." Vilain is presenting details of seven of the 50 genes to the annual meeting of the American Society of Human Genetics in Baltimore this week. Three of these genes are dominant in females and four are dominant in males. The next step for Vilain and his team will be to show that the genes in question really do influence brain sexuality—and not just in mice. This is likely to be a much tougher proposition than merely showing there are differences in expression. But if the findings are confirmed, they could one day yield blood tests that allow doctors to establish the brain sex of babies born with genitalia that share features of both sexes. At present doctors and parents have to guess which gender to assign for surgical "correction". We can infer from the last paragraph that ______.
/*simple ping program*/ struct sockaddr_in saddr; int rawsock; unsigned short in_cksum(unsigned short*addr, int len) { int sum=0; unsigned short res=0; while(1en＞1){ sum+=*addr++; len-=2; } if(len=1){ *((unsigned char *)(&res))=*((unsigned char *)addr); sum+=res; } sum=(sum＞＞16)+(sam & 0xffff); sum+=(sum＞＞16); res=～sum; return res; } void ping(int signo) { int len; int i; static unsigned short seq=0; char buff[8192]; struct timeval tv; struet icmp*icmph=(struct icmp * )buff; long*data=(long*)icmph→icmp_data; bzero(buff, 8192); gettimeofday(&tv, NULL); icmph→icmp_type=ICMP_ECHO; icmph→icmp_code=0; icmph→icmp_cksum=0; icmph→icmp_id=0; icmph→icmp_seq=0; icmph→icmp_id=getpid()&0xffff; icmph→icmp_seq=seq++; data[0]=tv.tv_sec; data[1]=tv.tv_usec; for(i=8; i＜ ; i++) icmph→icmp_data[i]=(unsigned char)i; icmph→icmp_cksum=in_cksum((unsigned short *)buff, 72); len; sendto(rawsock, buff, 72, 0, &saddr, sizeof(saddr)); alarm(1); } void sigint(int signo) { printf("CATCH SIGINT !!! \n"); close(rawsock); exit(0); } void dumppkt(char*buf, int len) { struct ip*iph=(struct ip*)buf; int i=iph→ip_h1*4; struct icmp*icmph=(struct icmp*)&buf[i]; long*data=(long*)iemph→icmp_data; struct timeval tv; gettimeofday(&tv, NULL); if(icmph→icmp_type! =ICMP_ECHOREPLY) return; if(icmph→icmp_id! =(getpid()&0xffff)) return; printf("From %s:ttl=% d seq=% d time=%.2f ms\n", inet_ntoa(iph→ip_src)，iph→ip_ttl, icmph→icmp_seq, (tv.tv_see-data[0])*1000.0+(tv.tv_usec-data[0])/1000.0)； } int main(int argc, char*argv[]) { int len; stuct timeval now; char recvbuff[8192]; if(1){ printf("%s aaa.bbb.ccc.ddd\n", argv[0]); exit(1); } rawsock=soeket(AF_INET, (2), IPPROTO_ICMP); if(rawsock＜0) { perror("soeket"); exit(1); } bzero ( &saddr, sizeof(saddr)); saddr.sin_family=(3); if( inet_aton( argv[1], &saddr.sin_addr) ＜0) { printf("invalid IP address: %s\n", argv[1]); exit(1); } signal(SICALRM, ping); signal(SICINT, sigint); alarm(1); while (1){ len=read (4), recvbuff, 8192); if( len＜0 && errno=EINTR) continue; else it( len＜0) perror("read"); else if( len＞0) dumppkt(recvbuff, len); } close (5); exit(0); }
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