Ocean acidification impacts on sperm mitochondrial membrane potential bring sperm swimming behaviour near its tipping point

Broadcast spawning marine invertebrates are susceptible to environmental stressors such as climate change, as their reproduction depends on the successful meeting and fertilization of gametes in the water column. Under near-future scenarios of ocean acidification, the swimming behaviour of marine invertebrate sperm is altered. We tested whether this was due to changes in sperm mitochondrial activity by investigating the effects of ocean acidification on sperm metabolism and swimming behaviour in the sea urchin Centrostephanus rodgersii. We used a fluorescent molecular probe (JC-1) and flow cytometry to visualize mitochondrial activity (measured as change in mitochondrial membrane potential, MMP). Sperm MMP was significantly reduced in delta pH -0.3 (35% reduction) and delta pH -0.5 (48% reduction) treatments, whereas sperm swimming behaviour was less sensitive with only slight changes (up to 11% decrease) observed overall. There was significant inter-individual variability in responses of sperm swimming behaviour and MMP to acidified seawater. We suggest it is likely that sperm exposed to these changes in pH are close to their tipping point in terms of physiological tolerance to acidity. Importantly, substantial inter-individual variation in responses of sperm swimming to ocean acidification may increase the scope for selection of resilient phenotypes, which, if heritable, could provide a basis for adaptation to future ocean acidification.

The responses of eight coral reef calcifiers to increasing partial pressure of CO2 do not exhibit a tipping point

The objective of this study was to investigate whether a tipping point exists in the calcification responses of coral reef calcifiers to CO2. We compared the effects of six partial pressures of CO2 (PCO2) from 28 Pa to 210 Pa on the net calcification of four corals (Acropora pulchra, Porites rus, Pocillopora damicornis, and Pavona cactus), and four calcified algae (Hydrolithon onkodes, Lithophyllum flavescens, Halimeda macroloba, and Halimeda minima). After 2 weeks of acclimation in a common environment, organisms were incubated in 12 aquaria for 2 weeks at the targeted PCO2 levels and net calcification was quantified. All eight species calcified at the highest PCO2 in which the calcium carbonate aragonite saturation state was ~1. Calcification decreased linearly as a function of increasing partial PCO2 in three corals and three algae. Overall, the decrease in net calcification as a function of decreasing pH was ~10% when ambient PCO2 (39 Pa) was doubled. The calcification responses of P. damicornis and H. macroloba were unaffected by increasing PCO2. These results are inconsistent with the notion that coral reefs will be affected by rising PCO2 in a response characterized by a tipping point. Instead, our findings combined among taxa suggest a gradual decline in calcification will occur, but this general response includes specific cases of complete resistance to rising PCO2. Together our results suggest that the overall response of coral reef communities to ocean acidification will be monotonic and inversely proportional to PCO2, with reef-wide responses dependent on the species composition of calcifying taxa.

Sustainable Development: The Search for the Tipping Point

The United Nations recently launched the Decade of Education for Sustainable Development. Literature indicates the need for an authoritative definition of sustainable development. Sustainable Human Development is analyzed through the lens of Gladwell’s The Tipping Point as a framework for guiding ethical development practice and instigating changes in human behavior.

The Business Case for (and Against) Restaurant Tipping

Recent interest in replacing tipping with service charges or higher service-inclusive menu pricing prompted this review of empirical evidence on the advantages and disadvantages to restaurants of these different compensation systems. The evidence indicates that these different pricing systems affect the attraction and retention of service workers, the satisfaction of customers with service, the actual and perceived costs of eating out, and the costs of hiring employees and doing business. However, the author comes away from the data believing that the biggest reason for restaurateurs to replace tipping is that the practice takes revenue away from them in the form of lower prices and gives it to servers in the form of excessively high tip income. The biggest reason for restaurateurs to keep tipping is that it allows them to reduce menu prices, which increases demand. Thus, restaurateurs’ decisions to keep voluntary tipping or not should ultimately depend on the relative strengths of these benefits. The more that a restaurant’s servers are overpaid relative to the back of house and the wealthier and less price-sensitive a restaurant’s customers are, the more the owner of that restaurant should consider abandoning tipping. By this reasoning, many upscale, expensive restaurants (especially those in states with no or small tip credits) probably should replace tipping with one of its alternatives.

Does Tipping Help to Attract and Retain Better Service Workers?

A survey of several hundred restaurant servers in the United States found that servers’ attitudes toward working for tips and average tip sizes were weakly related (at best) to their service-orientation, intended job-tenure, and occupational-tenure. These findings suggest that tipping does not substantially help to attract and retain more service-oriented workers. Restaurateurs can eliminate tipping at their restaurants without fear that doing so will reduce the quality of their wait-staff.

Black-White Wage Gap Among Restaurant Servers: A Replication, Extension, and Exploration of Consumer Racial Discrimination in Tipping

There is a rich history of social science research centering on racial inequalities that continue to be observed across various markets (e.g., labor, housing, and credit markets) and social milieus. Existing research on racial discrimination in consumer markets, however, is relatively scarce and that which has been done has disproportionately focused on consumers as the victims of race-based mistreatment. As such, we know relatively little about how consumers contribute to inequalities in their roles as perpetrators of racial discrimination. In response, in this paper we elaborate on a line of research that is only in its’ infancy stages of development and yet is ripe with opportunities to advance the literature on consumer racial discrimination and racial earnings inequities among tip dependent employees in the United States. Specifically, we analyze data derived from a large exit survey of restaurant consumers (n=378) in an attempt to replicate, extend, and further explore the recently documented effect of service providers’ race on restaurant consumers’ tipping decisions. Our results indicate that both White and Black restaurant customers discriminate against Black servers by tipping them less than their White coworkers. Importantly, we find no evidence that this Black tip penalty is the result of interracial differences in service skills possessed by Black and White servers. We conclude by delineating directions for future research in this neglected but salient area study.

Tip-over injuries in children under 5 years of age in Queensland 1999-2008

Furniture and appliance related injuries in children under 5 years of age accounts for an estimated 180 emergency presentations annually in Queensland. Injuries occur when children push or pull items over, climb and fall off furniture, or climb and tip the item over. Children under 2 years of age tend to injure themselves by pulling items over onto themselves Children over 2 years of age are more likely to be injured after climbing the item and either falling off or tipping the item over onto themselves. Tip over injuries (where the item falls over and injures the child) in children under 5 years of age account for an estimated 115 emergency presentations annually in Queensland. The item most commonly associated with a tip over injury is a television (with or without the cabinet) Prevention requires better design and selection of furniture with inherent stability coupled with mechanisms to install or fix less stable items

From entrepreneur to philanthropist : the “second half of the game”

This paper uses interviews with wealthy Australians to examine the progression from entrepreneurship to philanthropy in an Australian context. Understanding the characteristics, behaviours and motivations of this group of entrepreneurs turned philanthropists strengthens the links identified in international research between the entrepreneurship and philanthropic sectors. Three major themes emerging from the qualitative data are explored: first, the tipping points that move individuals (and their partners/families) between the two spheres of activity; and second, the strong motivations for giving that see entrepreneurs identified internationally as more generous than high net worth individuals whose wealth derives from other sources. The third major theme is the modes of giving that distinguish those with an entrepreneurship background from other philanthropists. The unique characteristics of a smaller sub-set of ultra high net worth donors are also explored, and areas for future study are highlighted.

The emerging role of the Board of Directors in enterprise business technology governance

In an increasingly business technology (BT) dependent world, the impact of the extraordinary changes brought about by the nexus of mobile and cloud technologies, social media and big data is increasingly being felt in the board room. As leaders of enterprises of every type and size, board directors can no longer afford to ignore, delegate or avoid BT-related decisions. Competitive, financial and reputational risk is increased if boards fail to recognize their role in governing technology as an asset and in removing barriers to improving enterprise business technology governance (EBTG). Directors’ awareness of the need for EBTG is increasing. However, industry research shows that board level willingness to rectify the gap between awareness and action is very low or non-existent. This literature review-based research identifies barriers to EBTG effectiveness. It provides a practical starting point for board analysis. We offer four outcomes that boards might focus on to ensure the organizations they govern are not left behind by those led by the upcoming new breed of technology-savvy leaders. Most extant research looks backward for examples, examining data pre-2010, the time when a tipping point in the personal and business use of multimedia and mobile-internet devices significantly deepened the impacts of the identified nexus technology forces, and began rapidly changing the way many businesses engage with their customers, employees and stakeholders. We situate our work amidst these nexus forces, discuss the board’s role in EBTG in this context, and modernize current definitions of enterprise technology governance. The primary limitation faced is the lack of scholarly research relating to EBTG in the rapidly changing digital economy. Although we have used recent (2011 - 2013) industry surveys, the volume of these surveys and congruence across them is significant in terms of levels of increased awareness and calls for increased board attention and competency in EBTG and strategic information use. Where possible we have used scholarly research to illustrate or discuss industry findings.