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71.
Opposition to transracial adoption on both sides of the Atlantic, has been based, in part, on the assumption that white parents cannot understand race or racism and thus cannot properly prepare children of multiracial heritage to cope with racism. In this article I draw on a seven-year ethnographic study to offer an intensive case study of white transracial birth parents that counters this racial logic. I draw on a subset of data collected from field research and in-depth interviews with 102 members of black-white interracial families in England. I provide an analysis of three practices that I discovered among white transracial birth parents who were attempting to cultivate ‘black’ identities in their children of multiracial heritage. I offer the concept of ‘racial literacy’ to theorize their parental labour as a type of anti-racist project that remains under the radar of conventional sociological analyses of racism and anti-racist social movements.  相似文献   
72.
We present a hands-on outdoor activity coupled with classroom discussion to teach students about wildlife habitat selection, the process by which animals choose where to live. By selecting locations or habitats with many benefits (e.g., food, shelter, mates) and few costs (e.g., predators), animals improve their ability to survive and reproduce. Biologists track animal movement using radio telemetry technology to study habitat selection so they can better provide species with habitats that promote population growth. We present a curriculum in which students locate “animals” (transmitters) using radio telemetry equipment and apply math skills (use of fractions and percentages) to assess their “animal's” habitat selection by comparing the availability of habitat types with the proportion of “animals” they find in each habitat type.  相似文献   
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74.
??????? 目的 探索在保证护理安全的基础上提升护理工作效率的方法。 方法 按实施不同制度的时间段将患者分为A组和B组,A组实行三级责任护理管理制度;B组在实行三级责任护理管理制度并对现有病区进行合理分区的基础上,依据患者危重分级和护理人员分层来分配每个床单位的责任护士(双向分层管理制度),两组进行护理总时数、所护理的患者人数、不同危重分级患者的平均护理时数、同一患者不同危重分级平均天数等比较。 结果 B组中不同分层护理人员所护理的患者危重分级与护理时数成正比,但总护理时数相近,所护理人数随危重分级提高而减少,危重分级1级患者平均住院天数明显下降。 结论 双向分层管理组相对于三级责任护理管理组更能保证护理安全、提升护理工作效率。  相似文献   
75.
The sentinel lymph node procedure is still under evaluation for the management of cervical and endometrial carcinomas. The aim of our study was to determine the diagnostic accuracy of single-photon emission computed tomography/computed tomography (SPECT/CT) for preoperative sentinel lymph node mapping in uterine cancers. Sixty-eight patients with cervical (n = 42) or endometrial carcinoma (n = 26) underwent preoperative lymphoscintigraphy for sentinel node mapping. Sentinel node detection rate with conventional planar imaging was similar to that of SPECT/CT (87.1 versus 91.8 %) in the whole cohort. However, SPECT/CT detected a higher number of sentinel nodes in more than one third of patients, affected by either cervical or endometrial carcinoma. The rate of non or insufficiently contributive procedures (lack of uptake or unilateral uptake) in endometrial carcinomas was 47 % with conventional planar imaging, and 30 % with SPECT/CT. Sensitivity of both procedures for the detection of metastatic nodes was 81.8 %, compared to 100 % for the intraoperative combined detection (gamma probe sonde and blue dye). The impact of SPECT/CT for the sentinel lymph node detection in cervical and endometrial carcinomas needs further evaluation. Nevertheless, SPECT/CT may provide additional information when conventional planar imaging detects only unilateral uptake, may improve identification of atypical localizations, and facilitate surgical approach.  相似文献   
76.
Cilia are microtubule-based hair-like organelles that project from the surface of most eukaryotic cells. They play critical roles in cellular motility, fluid transport and a variety of signal transduction pathways. While we have a good appreciation of the mechanisms of ciliary biogenesis and the details of their structure, many of their functions demand a more lucid understanding. One such function, which remains as intriguing as the time when it was first discovered, is how beating cilia in the node drive the establishment of left–right asymmetry in the vertebrate embryo. The bone of contention has been the two schools of thought that have been put forth to explain this phenomenon. While the ‘morphogen hypothesis’ believes that ciliary motility is responsible for the transport of a morphogen preferentially to the left side, the ‘two-cilia model’ posits that the motile cilia generate a leftward-directed fluid flow that is somehow sensed by the immotile sensory cilia on the periphery of the node. Recent studies with the mouse embryo argue in favour of the latter scenario. Yet this principle may not be generally conserved in other vertebrates that use nodal flow to specify their left–right axis. Work with the teleost fish medaka raises the tantalizing possibility that motility as well as sensory functions of the nodal cilia could be residing within the same organelle. In the end, how ciliary signalling is transmitted to institute asymmetric gene expression that ultimately induces asymmetric organogenesis remains unresolved.  相似文献   
77.
目的:探讨进展期胃癌脾门淋巴结(10组)转移的相关临床病理因素.方法:回顾分析了(2008-2011年)75例胃癌根治术伴10组淋巴结切除的进展期胃癌病例.分析了临床病理学因素和10组淋巴结转移的相关性.结果:本研究结果提示10组淋巴结转移的阳性率为52%.胃下部癌的转移率(20%)相对较低(P=0.000),大弯侧肿瘤的转移率高达76.2%.病灶的侵润深度及病理TNM分期与10组淋巴结阳性率密切相关,组织学类型或分化程度与10组淋巴结转移无统计学相关.病灶小于3 cm病例的10组淋巴结转移的阳性率为0%,而大于9 cm或Borrmann-Ⅳ的肿瘤患者的10组淋巴结转移的阳性率为100%.结论:10组淋巴结转移的高危因素包括:1.中上部胃癌;2.肿瘤位于胃大弯侧;3.大于3 cm; 4.侵达胃壁浆膜层.含以上高危因素的进展期胃癌根治手术中,建议常规行术中快速冰冻检查10组淋巴结是否存在转移;含2个以上高危因素的进展期胃癌建议行脾切除术,或如果技术条件具备应行保留脾的10组淋巴结清扫术以便最终获得R0切除.  相似文献   
78.
目的:探讨淋巴结转移阴性胃癌患者的临床病理特征以及预后影响因素。方法:收集2000年1月至2009年1月我院收治的胃癌患者325例,其中经病理检查显示淋巴结转移阴性的105例患者作为阴性组(LN-组),另229例阳性患者作为阳性组(LN+组),比较两组的临床病理特征及临床预后。结果:LN-组的肿瘤直径、浸润深度及术后化疗与LN+组比较差异显著(P0.05);LN-组的5年生存率为76.2%,显著高于LN+组的43.2%(P0.05)。未透浆膜的LN-患者3年、5年生存率显著高于浸透浆膜者,术后化疗的LN-患者5年生存率显著高于未化疗者(P0.05),肿瘤直径5 cm的LN-患者3、5年生存率显著高于≥5 cm者(P0.05)。单因素分析显示浸润深度、肿瘤大小及术后化疗与LN-胃癌患者的预后具有密切关系(P0.05)。COX多因素分析显示浸润深度是影响LN-胃癌患者临床预后的独立因素(P0.05)。结论:淋巴结转移阴性胃癌患者的病灶多位于中下部,男性多于女性,发病年龄多在60岁以内,肿瘤直径多不超过5 cm,浸润深度多未浸透浆膜,临床预后优于淋巴结转移阳性胃癌患者,浸润深度是影响淋巴结转移阴性胃癌患者临床预后的独立因素。  相似文献   
79.
Critical transitions are qualitative changes of state that occur when a stochastic dynamical system is forced through a critical point. Many critical transitions are preceded by characteristic fluctuations that may serve as model‐independent early warning signals, implying that these events may be predictable in applications ranging from physics to biology. In nonbiological systems, the strength of such early warning signals has been shown partly to be determined by the speed at which the transition occurs. It is currently unknown whether biological systems, which are inherently high dimensional and typically display low signal‐to‐noise ratios, also exhibit this property, which would have important implications for how ecosystems are managed, particularly where the forces exerted on a system are anthropogenic. We examine whether the rate of forcing can alter the strength of early warning signals in (1) a model exhibiting a fold bifurcation where a state shift is driven by the harvesting of individuals, and (2) a model exhibiting a transcritical bifurcation where a state shift is driven by increased grazing pressure. These models predict that the rate of forcing can alter the detectability of early warning signals regardless of the underlying bifurcation the system exhibits, but that this result may be more pronounced in fold bifurcations. These findings have important implications for the management of biological populations, particularly harvested systems such as fisheries, and suggest that knowing the class of bifurcations a system will manifest may help discriminate between true‐positive and false‐positive signals.  相似文献   
80.
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