Keeping up with the digital age: How the American Red Cross uses social media to build relationships

Forty individuals from the American Red Cross were interviewed to explore the use of social media in communicating with key publics. Results show that practicing public relations through social media is effective and necessary in the emerging digital age, as shown through the Red Cross’ development of a two-way dialogue with younger constituents, the media, and the community. This two-way dialogue has been accomplished primarily through Twitter and Facebook, with barriers such as lack of staff and time, and opportunities to improve National Headquarters and local chapter relations. The insights shared by the American Red Cross are useful for both public relations scholars and professionals to help them understand and apply social media practices to build strong, lasting relationships.     

RDS编码器的实现技术

介绍了广播数据系统（ＲａｄｉｏｎＤａｔａＳｙｓｔｅｍ，简称ＲＳＤ）利用现有调频立体声电台，在其基带频谱的上边界外（５７ｋＨｚ±２ｋＨｚ处）附加一块用ＤＰＳＫ方式调制的数据信息的频谱（一般称其为附加信近）多工地传送广播信息的基本原理，讨论了发端编码器的结构、实现方案以及波形成形截短的影响，并给出了一个实际模型。     

螺旋天线宽带阻抗匹配技术的研究

介绍了一种用渐变镜像传输线阻抗变换器来实现螺旋天线与50Ω馈线之间的宽带匹配技术.实验结果表明,采用渐变镜像传输线阻抗变换器能在2:1的频带范围内实现 ρ<2.     

Immigration,Ethnicity, and Conflict: The California Chinese, 1849–1882*

Drawing on Bonacich's split market theory, the work of Hechter and Blalock on ethnic conflict, and the literature on social movements, the authors develop a model of factors producing conflict between native and immigrant workers. The model identifies the relative size of the immigrant group, the growth of the immigrant population, the desirability of jobs held by immigrant workers, economic conditions, the development of racist ideology among native workers, and the organization of native workers as factors possibly explaining the frequency of incidents of overt ethnic conflict and efforts to institutionalize discrimination through government action. The model is assessed by examining the situation of Chinese immigrants in California between 1849 and 1882. The data suggest that poor economic conditions, a well-developed racist ideology, and well-organized native workers best explain incidents of ethnic conflict and successful efforts to obtain discriminatory government action.     

A note on information loss in analyzing a mixture model of count data

In this note we consider estimation of a mixture model of count data which is composed of two discrete random variables. Conditional and unconditional estimation procedures are given for estimating the unknown parameter(s) of interest using the likelihood function. Asymptotic relative efficiencies are given to examine the amount of information loss in using the two estimation procedures. Specifically, we study the change in asymptotic relative efficiency, if any, in different parameter settings.     

Linking dichotomous segregation with multi-group segregation: Weighted segregation ratios in selected U.S. metropolitan areas

The U.S. residential landscape is increasingly multi-racial and multi-ethnic, giving rise to the question of how to compare dichotomous segregation among multiple groups living in the same area. To address the problem in the existing dichotomous approach, which offers no common basis for comparing dichotomous segregation among multiple groups, this paper develops a weighted segregation ratio approach based on Theil’s segregation index and its additive decomposability. This approach can be used to bridge information obtained from dichotomous segregation between specific groups (such as black-white and black-Hispanic), and dichotomous segregation between group and non-group (such as white-non-white and black-non-black) in previous studies. We apply both dichotomous and weighted segregation ratio approaches to 1990 and 2000 U.S. census data. Results are interpreted for five selected metropolitan areas as well as for the weighted national average. This new approach yields distinctive findings that portray the complicated process of residential segregation, including the increasing significance of Hispanic segregation and Asian segregation in the decade from 1990 to 2000.     

Out of Sight,Out of Mind? Patterns of Transnational Contact Among Chinese and Indian Immigrants in Toronto1

There has been considerable discussion in recent decades about the integration patterns of new immigrants. Recognizing advancements in technology and the increased economic integration of countries, some researchers have suggested that the emerging integration trend for immigrants is the transnational pattern, whereby immigrants maintain contact with the home countries. To advance the discussion, this study focuses on general transnational contact, a basic form of transnational activity. The study draws from recently collected large‐scale survey data to explore the patterns of transnational contact within two recent immigrant groups, Asian Indians and Chinese, in Toronto. Our findings show that only a small percentage of immigrants maintain intensive and extensive transnational contact. As well, our findings are less consistent with the transnational perspective than with the assimilation perspective on the effects of socioeconomic background on transnational contacts.     

Borrowing Information across Populations in Estimating Positive and Negative Predictive Values

A marker's capacity to predict risk of a disease depends on disease prevalence in the target population and its classification accuracy, i.e. its ability to discriminate diseased subjects from non-diseased subjects. The latter is often considered an intrinsic property of the marker; it is independent of disease prevalence and hence more likely to be similar across populations than risk prediction measures. In this paper, we are interested in evaluating the population-specific performance of a risk prediction marker in terms of positive predictive value (PPV) and negative predictive value (NPV) at given thresholds, when samples are available from the target population as well as from another population. A default strategy is to estimate PPV and NPV using samples from the target population only. However, when the marker's classification accuracy as characterized by a specific point on the receiver operating characteristics (ROC) curve is similar across populations, borrowing information across populations allows increased efficiency in estimating PPV and NPV. We develop estimators that optimally combine information across populations. We apply this methodology to a cross-sectional study where we evaluate PCA3 as a risk prediction marker for prostate cancer among subjects with or without previous negative biopsy.     

“No strings attached”: A qualitative exploration of gay and bisexual men’s motivations for and attitudes toward engaging in casual sex while on vacation

Prior quantitative research with gay and bisexual men (GBM) has documented high rates of sexual risk behavior during recreational travel. Although some associations are known (e.g., substance use at the tourist destination is associated with sexual risk), less is known about GBM’s motivations for travel and the cognitive and attitudinal factors that influence their sexual behavior while vacationing. In the present study, we conducted qualitative interviews with 46 GBM recruited from three popular gay tourist destinations. Using the Health Belief Model (HBM) as a guiding theoretical framework, the findings of the study revealed that the gay-friendly, tropical, relaxing environments resulted in men letting their guard down and engaging in more risk than when they are at home. Various barriers such as peer pressure and substance use affect GBM’s ability to engage in healthier behaviors while traveling, with condom negotiation and HIV status disclosure as additional issues that impact the sex practices of this population. Results highlight the applicability of HBM constructs to provide insight for intervention development for this population.