Effects of Growth Temperatures on the Fatty Acid Composition of Isolated Chloroplasts From Two Species Differing in Heat Sensitivity

Lipid analyses of chloroplasts isolated from wheat (Triticum aestivum L. cv. Arthur) and milo (Sorghum bicolor cv. Funk\u27s hybrid 522) suggest no major heat effect on lipid class distribution. Assuming milo is more heat tolerant than wheat and that increased saturated/unsaturated fatty acid values increase thermal stability, changes in sulfoquinovosyldiglyceride (SL) appear to be more important than phosphatidylglycerol (PG) in conferring thermal stability to isolated chloroplasts

Can Intertemporal Choice Experiments Elicit Time Preferences for Consumption? Yes

The most popular experimental method for eliciting time preferences involves subjects making choices over smaller, sooner amounts of money and larger, later amounts of money. Under some theoretically possible configurations of preferences and procedures, the discount rates inferred from these choices could lead to misleading inferences about time preferences for consumption. Using a direct empirical test, we show that those configurations of preferences are empirically implausible.

The Independence Axiom and the Bipolar Behaviorist

Developments in the theory of risk require yet another evaluation of the behavioral validity of the independence axiom. This axiom plays a central role in most formal statements of expected utility theory, as well as popular alternative models of decision-making under risk, such as rank-dependent utility theory. It also plays a central role in experiments used to characterize the way in which risk preferences deviate from expected utility theory. If someone claims that individuals behave as if they "probability weight" outcomes, and hence violate the independence axiom, it is invariably on the basis of experiments that must assume the independence axiom. We refer to this as the Bipolar Behavioral Hypothesis: behavioral economists are pessimistic about the axiom when it comes to characterizing how individuals directly evaluate two lotteries in a binary choice task, but are optimistic about the axiom when it comes to characterizing how individuals evaluate multiple lotteries that make up the incentive structure for a multiple-task experiment. Building on designs that have a long tradition in experimental economics, we offer direct tests of the axiom and the evidence for probability weighting. We reject the Bipolar Behavioral Hypothesis: we find that nonparametric preferences estimated for the rank-dependent utility model are significantly affected when one elicits choices with procedures that require the independence assumption, as compared to choices with procedures that do not require that assumption. We also demonstrate this result with familiar parametric preference specifications, and draw general implications for the empirical evaluation of theories about risk.

Inducing Risk Neutral Preferences with Binary Lotteries: A Reconsideration

We evaluate the binary lottery procedure for inducing risk neutral behavior. We strip the experimental implementation down to bare bones, taking care to avoid any potentially confounding assumption about behavior having to be made. In particular, our evaluation does not rely on the assumed validity of any strategic equilibrium behavior, or even the customary independence axiom. We show that subjects sampled from our population are generally risk averse when lotteries are defined over monetary outcomes, and that the binary lottery procedure does indeed induce a statistically significant shift towards risk neutrality. This striking result generalizes to the case in which subjects make several lottery choices and one is selected for payment.

“You Have to Be Strong and Struggle”: Stigmas as a Determinants of Inequality for Female Survivors of Sex Trafficking in Cambodia

Across the globe, human trafficking survivors have reported facing stigma and discrimination after reintegrating into communities. What makes stigma particularly dangerous is that it threatens what is “most at stake” in our lives, our close personal relationships and our personal life values. This paper explores longitudinal data from the Chab Dai Butterfly Longitudinal Research Project to document and describe forms of stigma and discrimination faced by survivors of sexual exploitation and trafficking living in Cambodian communities. Our research suggests stigmas associated with sex trafficking are a “fundamental determinant” of social inequality for many female survivors following reintegration. In this study, 56 women survivors discussed their encounters with stigma and discrimination interspersed with coping strategies and resilience attributes used to navigate life experiences. The majority (70%) spoke about contending with cultural stigma together with stigma from human trafficking experiences. Four main stigma causes dominated survivor narratives: gender, sex work, socioeconomic status, and marriageability. We use these causes, in combination with the voices of survivors, to develop a conceptual model of cohort experiences with stigma in Cambodia. Many survivors are conscious of negative stereotypes in their home communities before trafficking and discuss their struggles with self-stigmatizing thoughts and labels as they reintegrate back into their communities. Survivor discussions regarding stigmas associated with sex work show intense and persistent stigma layered over existing cultural stigmas and connected with a wide variety of societal discrimination and negative outcomes. This assessment identifies multiple disadvantaged outcomes for survivors in education, relationships, marital rights, and gender-based violence. We argue that these outcomes impact survivors\u27 access/barriers to resources and life conditions related to job skills, employment opportunities, improving their socioeconomic status, mental and physical health, and other perceptions of family harmony, societal honor, and personal well-being

Radionuclide Contaminant Burdens in Arctic Marine Mammals Harvested During Subsistence Hunting

We conducted gamma spectrometric analyses on more than 200 arctic marine mammal tissue samples. These samples were primarily provided by subsistence hunters from northern Alaska, with a smaller number of samples from the Resolute region in Canada. The majority of samples (>90%) had detectable levels of the anthropogenic radionuclide 137Cs, with a mean level observed in all samples of 0.67 Bq/kg dry weight ± 0.81 (SD). Converted to wet weight, the mean was 0.21 Bq/kg ± 0.19 SD. The median activity observed was 0.45 Bq/kg dry weight (0.18 Bq/kg wet weight) with a range from detection limits to 6.7 Bq/kg dry weight (1.1 Bq/kg wet weight). These findings confirm expectations that current anthropogenic gamma emitter burdens in marine mammals used in the North American Arctic as subsistence food resources are well below activities that would normally merit public health concern (~1000 Bq/kg wet weight). Some differences among species and tissues were observed. Beluga tissues had slightly higher mean burdens of 137Cs overall, and epidermis and muscle tissues in bowhead and beluga whales typically had higher burdens than other tissues analyzed. Low levels of the neutron activation product 108mAg (half-life 418 yr.), probably bioaccumulated from bomb fallout sources, were observed in 16 of 17 beluga livers analyzed, but were not found in any other tissues of beluga or in any other species sampled. A subset of 39 samples of various tissues was analyzed for the alpha and beta emitters 239,240Pu and 90Sr. Plutonium levels were near the threshold of detectability (~0.1 Bq/kg dry weight) in 6 of the 39 samples; all other samples had no detectable plutonium. A detectable level of 90Sr (10.3 ± 1.0 Bq/kg dry weight) was observed in only one of the 39 samples analyzed, a bowhead epidermis sample. Although the accumulation of 108mAg has not been previously reported in any marine mammal livers, all of our analytical measurements indicate that only very low levels of anthropogenic radioactivity are associated with marine mammals harvested and consumed in the North American Arctic.On a effectué des analyses gamma-spectrométriques sur plus de 200 échantillons de tissus prélevés sur des mammifères marins. La plupart de ces échantillons étaient fournis par des chasseurs de subsistance de l'Alaska septentrional, et un petit nombre venaient de la région de Resolute au Canada. La majorité des échantillons (> 90 p. cent) contenaient des niveaux détectables du radionucléide anthropique 137Cs, avec un niveau moyen observé dans tous les échantillons de 0,67 Bq/kg de poids sec ± 0,81 (écart-type). Convertie en poids frais, la moyenne était de 0,21 Bq/kg ± 0,19 d'écart-type. L'activité médiane observée était de 0,45 Bq/kg de poids sec (0,18 Bq/kg de poids frais) avec une fourchette allant des seuils de détection jusqu'à 6,7 Bq/kg de poids sec (1,1 Bq/kg de poids frais). Ces résultats confirment les réponses prévues, à savoir que les charges actuelles des émetteurs gamma anthropiques présentes chez les mammifères marins utilisés en Amérique du Nord comme ressource de subsistance sont bien inférieures aux niveaux qui voudraient normalement qu'on s'inquiète pour la santé publique (~1000 Bq/kg de poids frais). On a observé certaines différences dans les espèces et les tissus. Dans l'ensemble, les tissus prélevés sur le bélouga contenaient des charges moyennes de 137Cs légèrement plus élevées, et l'épiderme et les tissus musculaires de la baleine boréale et du bélouga avaient généralement des charges supérieures à celles trouvées dans les autres tissus analysés. Dans 16 des 17 foies de bélouga analysés, on a observé de faibles niveaux du produit d'activation neutronique 108mAg (demi-vie 418 années), dont la bioaccumulation est probablement due à des retombées de bombes atomiques, mais on n'en a observé aucune trace dans les autres tissus du bélouga ou de toute autre espèce échantillonnée. On a analysé un sous-ensemble de 39 échantillons provenant de tissus divers pour savoir s'ils contenaient des émetteurs alpha et bêta 239,240Pu et 90Sr. Dans 6 des 39 échantillons, les niveaux de plutonium étaient proches du seuil de détectabilité (~ 0,1 Bq/kg de poids sec), et on n'a pas trouvé de plutonium détectable dans aucun des autres échantillons. On a observé un niveau détectable de 90Sr (10,3 ± 1,0 Bq/kg de poids sec) dans un seul des 39 échantillons analysés, soit un échantillon d'épiderme de baleine boréale. Bien qu'on n'ait jamais rapporté auparavant une accumulation de 108mAg dans le foie d'un mammifère marin, toutes nos mesures analytiques révèlent que les mammifères marins faisant l'objet d'une activité d'exploitation et consommés dans l'Arctique nord-américain ne présentent que de très faibles niveaux de radioactivité anthropique

Fear effects and group size interact to shape herbivory on coral reefs

Fear of predators (‘fear effects’) is an important determinant of foraging decisions by consumers across a range of ecosystems. Group size is one of the main behavioural mechanisms for mitigating fear effects while also providing foraging benefits to group members. Within coral reef ecosystems, fear effects have been shown to influence the feeding rates of herbivorous fishes, a key functional group that prevents macroalgal overgrowth. Yet, how fear effects and group size interact to shape macroalgal removal on coral reefs remains unclear. Here, we conducted field-based experiments using models of a common piscivorous fish, the leopard coral grouper Plectropomus leopardus and a series of macroalgal Sargassum ilicifolium assays positioned at increasing distances from the models (1, 2, 3 and 4 m) on two coral reefs in Singapore to investigate how acute fear effects shape the intensity of herbivory, and whether these effects were influenced by variation in the group size of herbivorous fishes feeding on the assays. We found acute fear effects strongly influenced the foraging behaviour of herbivorous fishes over small spatial scales. Rates of Sargassum biomass removal, feeding rates and the total number of individual feeding events were all lower near the predator model. These effects dissipated rapidly with increasing distance from the predator model and were undetectable at a distance of 4 m. We also found generally larger group sizes of herbivorous fishes further from the predator model, presumably reflecting decreased risk. Furthermore, the number of individual bites/event increased significantly with increasing group size for two common browsing fishes, Siganus virgatus and Siganus javus. Our findings highlight that acute fear effects influence the distribution and intensity of herbivory over small spatial scales. Fear effects also interacted with herbivore group size resulting in changes in the number of individual feeding events and bite rates that collectively shape the realized ecosystem function of macroalgal removal on coral reefs. Group size is an important context-dependent factor that should be considered when examining fear effects on coral reefs

Risk preferences, time preferences, and smoking behavior

There is a rich theoretical literature in economics which models habit‐forming behaviors, of which addiction is the exemplar, but there is a paucity of experimental economic studies eliciting and comparing the preferences that economic theory suggests may differ between addicts and nonaddicts. We evaluate an incentive‐compatible risk and time preference experiment conducted on a sample of student smokers and nonsmokers at the University of Cape Town in 2012. We adopt a full information maximum likelihood statistical framework, which is consistent with the data generating processes proposed by structural theories and accounts for subject errors in decision making, to explore the relationship between risk preferences, time preferences, and addiction. Across different theories and econometric specifications, we find no differences in the risk preferences of smokers and nonsmokers but do find that smokers discount significantly more heavily than nonsmokers. We also identify a nonlinear effect of smoking intensity on discounting behavior and find that smoking intensity increases the likelihood of discounting hyperbolically, which means heavier smokers may be more prone to time inconsistency and more recalcitrant to treatment. These results highlight the importance of the theory‐experimental design‐econometric trinity and have important implications for theories of addiction

Antagonism of STAT3 signalling by Ebola virus

Many viruses target signal transducers and activators of transcription (STAT) 1 and 2 to antagonise antiviral interferon signalling, but targeting of signalling by other STATs/cytokines, including STAT3/interleukin 6 that regulate processes important to Ebola virus (EBOV) haemorrhagic fever, is poorly defined. We report that EBOV potently inhibits STAT3 responses to interleukin-6 family cytokines, and that this is mediated by the interferon-antagonist VP24. Mechanistic analysis indicates that VP24 effects a unique strategy combining distinct karyopherin-dependent and karyopherin-independent mechanisms to antagonise STAT3-STAT1 heterodimers and STAT3 homodimers, respectively. This appears to reflect distinct mechanisms of nuclear trafficking of the STAT3 complexes, revealed for the first time by our analysis of VP24 function. These findings are consistent with major roles for global inhibition of STAT3 signalling in EBOV infection, and provide new insights into the molecular mechanisms of STAT3 nuclear trafficking, significant to pathogen-host interactions, cell physiology and pathologies such as cancer