Pay Dispersion and Performance in Teams

Extant research offers conflicting predictions about the effect of pay dispersion on team performance. We collected a unique dataset from the Italian soccer league to study the effect of intra-firm pay dispersion on team performance, under different definitions of what constitutes a “team”. This peculiarity of our dataset can explain the conflicting evidence. Indeed, we also find positive, null, and negative effects of pay dispersion on team performance, using the same data but different definitions of team. Our results show that when the team is considered to consist of only the members who directly contribute to the outcome, high pay dispersion has a detrimental impact on team performance. Enlarging the definition of the team causes this effect to disappear or even change direction. Finally, we find that the detrimental effect of pay dispersion is due to worse individual performance, rather than a reduction of team cooperation.     

Reciprocity on the Hardwood: Passing Patterns among Professional Basketball Players

Past theory and research view reciprocal resource sharing as a fundamental building block of human societies. Most studies of reciprocity dynamics have focused on trading among individuals in laboratory settings. But if motivations to engage in these patterns of resource sharing are powerful, then we should observe forms of reciprocity even in highly structured group environments in which reciprocity does not clearly serve individual or group interests. To this end, we investigated whether patterns of reciprocity might emerge among teammates in professional basketball games. Using data from logs of National Basketball Association (NBA) games of the 2008–9 season, we estimated a series of conditional logistic regression models to test the impact of different factors on the probability that a given player would assist another player in scoring a basket. Our analysis found evidence for a direct reciprocity effect in which players who had “received” assists in the past tended to subsequently reciprocate their benefactors. Further, this tendency was time-dependent, with the probability of repayment highest soon after receiving an assist and declining as game time passed. We found no evidence for generalized reciprocity – a tendency to “pay forward” assists – and only very limited evidence for indirect reciprocity – a tendency to reward players who had sent others many assists. These findings highlight the power of reciprocity to shape human behavior, even in a setting characterized by extensive planning, division of labor, quick decision-making, and a focus on inter-group competition.     

Cooperating elephants mitigate competition until the stakes get too high

Cooperation is ubiquitous in the animal kingdom as it aims to maximize benefits through joint action. Selection, however, may also favor competitive behaviors that could violate cooperation. How animals mitigate competition is hotly debated, with particular interest in primates and little attention paid thus far to nonprimates. Using a loose-string pulling apparatus, we explored cooperative and competitive behavior, as well as mitigation of the latter, in semi-wild Asian elephants (Elephas maximus). Our results showed that elephants first maintained a very high cooperation rate (average = 80.8% across 45 sessions). Elephants applied “block,” “fight back,” “leave,” “move side,” and “submission” as mitigation strategies and adjusted these strategies according to their affiliation and rank difference with competition initiators. They usually applied a “fight back” mitigation strategy as a sanction when competition initiators were low ranking or when they had a close affiliation, but were submissive if the initiators were high ranking or when they were not closely affiliated. However, when the food reward was limited, the costly competitive behaviors (“monopoly” and “fight”) increased significantly, leading to a rapid breakdown in cooperation. The instability of elephant cooperation as a result of benefit reduction mirrors that of human society, suggesting that similar fundamental principles may underlie the evolution of cooperation across species.

This study shows that in a task requiring coordinated pulling, elephants compete for access to food but work to mitigate competition in order to maintain cooperation. If the cost of competition becomes too high, however, cooperation breaks down entirely. This behavior mirrors that seen in humans and other great apes, suggesting that certain cooperative mechanisms are not unique to primates.     

Drug Resistance in Natural Isolates of Leishmania donovani s.l. Promastigotes Is Dependent of Pgp170 Expression

Resistance of pathogens to drugs is a growing concern regarding many diseases. Parasites like Leishmania, Plasmodium and Entamoeba histolytica; and neoplastic cells, present the multidrug-resistant phenotype rendering chemotherapy ineffective. The acquired resistance of Leishmania to antimony has generated intense research on the mechanisms involved but the question has not yet been resolved. To test the hypothesis that drug efflux in Leishmania, as measured by flow cytometry using the fluorescent dye Rhodamine-123, is largely dependent on the number of efflux pumps an isolate can express, the amount of Pgp 170 molecules was assessed in ten field isolates (5 “resistant” and 5 “susceptible”) using: Western Blotting, Confocal and Transmission Electron Microscopy, and proteomics. Their survival after exposure to three antileishmanial drugs, in vitro, was evaluated and clinical data were compared to the in vitro results. All isolates were resistant to Glucantime but susceptible to Miltefosine, whilst Amphotericin B was more effective on the “susceptible” isolates. The MDR gene, expressing the transmembrane efflux pump Pgp 170, appears to play a key role in the phenomenon of drug resistance. When “susceptible” versus “resistant” parasites were compared, it was shown that the higher the number of Pgp 170 molecules the higher the Rhodamine-123 efflux from the parasite body and, when exposed to the drug, the number of efflux pumps increased. However, the rate of this increase was not linear and it is possible that there is a maximum number of Pgp 170 molecules an isolate can express. Nevertheless, the phenomenon is a complex one and other factors and proteins are involved in which the HSP-70 group proteins, detected in the “resistant” isolates, may play a significant role.     

The Effectiveness of a ‘Train the Trainer’ Model of Resuscitation Education for Rural Peripheral Hospital Doctors in Sri Lanka

Background

Sri Lankan rural doctors based in isolated peripheral hospitals routinely resuscitate critically ill patients but have difficulty accessing training. We tested a train-the-trainer model that could be utilised in isolated rural hospitals.

Methods

Eight selected rural hospital non-specialist doctors attended a 2-day instructor course. These “trained trainers” educated their colleagues in advanced cardiac life support at peripheral hospital workshops and we tested their students in resuscitation knowledge and skills pre and post training, and at 6- and 12-weeks. Knowledge was assessed through 30 multiple choice questions (MCQ), and resuscitation skills were assessed by performance in a video recorded simulated scenario of a cardiac arrest using a Resuci Anne Skill Trainer mannequin.

Results/Discussion/Conclusion

Fifty seven doctors were trained. Pre and post training assessment was possible in 51 participants, and 6-week and 12-week follow up was possible for 43, and 38 participants respectively. Mean MCQ scores significantly improved over time (p<0.001), and a significant improvement was noted in “average ventilation volume”, “compression count”, and “compressions with no error”, “adequate depth”, “average depth”, and “compression rate” (p<0.01). The proportion of participants with compression depth ≥40mm increased post intervention (p<0.05) and at 12-week follow up (p<0.05), and proportion of ventilation volumes between 400-1000mls increased post intervention (p<0.001). A significant increase in the proportion of participants who “checked for responsiveness”, “opened the airway”, “performed a breathing check”, who used the “correct compression ratio”, and who used an “appropriate facemask technique” was also noted (p<0.001). A train-the-trainer model of resuscitation education was effective in improving resuscitation knowledge and skills in Sri Lankan rural peripheral hospital doctors. Improvement was sustained to 12 weeks for most components of resuscitation knowledge and skills. Further research is needed to identify which components of training are most effective in leading to sustained improvement in resuscitation.     

Accelerated Wound Closure In Vitro by Fibroblasts from a Subgroup of Cleft Lip/Palate Patients: Role of Transforming Growth Factor-α

In a fraction of patients surgically treated for cleft lip/palate, excessive scarring disturbs maxillary growth and dento-alveolar development. Since certain genes are involved in craniofacial morphogenesis as well as tissue repair, a primary defect causing cleft lip/palate could lead to altered wound healing. We performed in vitro wound healing assays with primary lip fibroblasts from 16 cleft lip/palate patients. Nine foreskin fibroblast strains were included for comparison. Cells were grown to confluency and scratch wounds were applied; wound closure was monitored morphometrically over time. Wound closure rate showed highly significant differences between fibroblast strains. Statistically, fibroblast strains from the 25 individuals could be divided into three migratory groups, namely “fast”, “intermediate”, and “slow”. Most cleft lip/palate fibroblasts were distributed between the “fast” (5 strains) and the “intermediate” group (10 strains). These phenotypes were stable over different cell passages from the same individual. Expression of genes involved in cleft lip/palate and wound repair was determined by quantitative PCR. Transforming growth factor-α mRNA was significantly up-regulated in the “fast” group. 5 ng/ml transforming growth factor-α added to the culture medium increased the wound closure rate of cleft lip/palate strains from the “intermediate” migratory group to the level of the “fast”, but had no effect on the latter group. Conversely, antibody to transforming growth factor-α or a specific inhibitor of its receptor most effectively reduced the wound closure rate of “fast” cleft lip/palate strains. Thus, fibroblasts from a distinct subgroup of cleft lip/palate patients exhibit an increased migration rate into wounds in vitro, which is linked to higher transforming growth factor-α expression and attenuated by interfering with its signaling.     

On the validation of crystallographic symmetry and the quality of structures

In 2008, Zwart and colleagues observed that the fraction of the structures deposited in the PDB alleged to have “pseudosymmetry” or “special noncrystallographic symmetry” (NCS) was about 6%, and that this percentage was rising annually. A few years later, Poon and colleagues found that 2% of all the crystal structures in the PDB belonged to higher symmetry space groups than those assigned to them. Here, I report an analysis of the X-ray diffraction data deposited for this class of structures, which shows that most of the “pseudosymmetry” and “special NCS” that has been reported is in fact true crystallographic symmetry (CS). This distinction is important because the credibility of crystal structures depends heavily on quality control statistics such as R_free that are unreliable when they are computed incorrectly, which they often are when CS is misidentified as “special NCS” or “pseudosymmetry”. When mistakes of this kind are made, artificially low values of R_free can give unjustified confidence in the accuracy of the reported structures.     

Cooperation and opportunism in Galapagos sea lion hunting for shoaling fish

For predators, cooperation can decrease the cost of hunting and potentially augment the benefits. It can also make prey accessible that a single predator could not catch. The degree of cooperation varies substantially and may range from common attraction to a productive food source to true cooperation involving communication and complementary action by the individuals involved. We here describe cooperative hunting of Galapagos sea lions (Zalophus wollebaeki) for Amberstripe scad (Decapterus muroadsi), a schooling, fast swimming semipelagic fish. A group of 6–10 sea lions, usually females only, drove scad over at least 600–800 m from open water into a cove where, in successful hunts, they drove them ashore. Frequently, these “core hunters” were joined toward the final stages of the hunt by another set of opportunistic sea lions from a local colony at that beach. The “core hunters” did not belong to that colony and apparently were together coming toward the area specifically for the scad hunt. Based on the observation of 40 such hunts from 2016 to 2020, it became evident that the females performed complementary actions in driving the scad toward the cove. No specialization of roles in the hunt was observed. All “core hunters” and also opportunistically joining sea lions from the cove shared the scad by randomly picking up a few of the 25–300 (mean 100) stranded fish as did scrounging brown pelicans. In one of these hunts, four individual sea lions were observed to consume 7–8 fish each in 25 s. We conclude that the core hunters must communicate about a goal that is not present to achieve joint hunting but presently cannot say how they do so. This is a surprising achievement for a species that usually hunts singly and in which joint hunting plays no known role in the evolution of its sociality.     

Molecular Evidence for the Broad Distribution of Anaerobic Ammonium-Oxidizing Bacteria in Freshwater and Marine Sediments

Previously available primer sets for detecting anaerobic ammonium-oxidizing (anammox) bacteria are inefficient, resulting in a very limited database of such sequences, which limits knowledge of their ecology. To overcome this limitation, we designed a new primer set that was 100% specific in the recovery of ~700-bp 16S rRNA gene sequences with >96% homology to the “Candidatus Scalindua” group of anammox bacteria, and we detected this group at all sites studied, including a variety of freshwater and marine sediments and permafrost soil. A second primer set was designed that exhibited greater efficiency than previous primers in recovering full-length (1,380-bp) sequences related to “Ca. Scalindua,” “Candidatus Brocadia,” and “Candidatus Kuenenia.” This study provides evidence for the widespread distribution of anammox bacteria in that it detected closely related anammox 16S rRNA gene sequences in 11 geographically and biogeochemically diverse freshwater and marine sediments.     

Primary Events, Energy Transfer, and Reactions in Photosynthetic Units: A Connected Model of the Photosynthetic Unit

The concept of photosynthetic unit (PSU) is reviewed in the light of the authors' results in the fields of fluorescence and luminescence (delayed light). Models of PSU are mainly distinguished by the amount of exciton exchange which is allowed between units. The “separate” model, with its “first-order” character, is not consistent with fluorescence kinetic data. The sigmoidal rise of fluorescence under actinic light is best explained by “nonseparate” models; however, most of these models assume a delocalization of excitons or centers. The “connected” model introduced here is not subject to this criticism. It discloses a new effect (the “îlot” effect): a nonrandom grouping of fluorescent units the consequences of which are discussed. It is noted that a “two-quantum” model for the photochemical reaction gives results very similar to those of the connected model. A relation between luminescence intensity and fluorescence yield is seen as a necessary consequence of the PSU concept. Its meaning is different in separate and nonseparate models. This relation is discussed in connection with the true system II fluorescence emission.     

Uncovering a Microbial Enigma: Isolation and Characterization of the Streamer-Generating,Iron-Oxidizing,Acidophilic Bacterium “Ferrovum myxofaciens”

A betaproteobacterium, shown by molecular techniques to have widespread global distribution in extremely acidic (pH 2 to 4) ferruginous mine waters and also to be a major component of “acid streamer” growths in mine-impacted water bodies, has proven to be recalcitrant to enrichment and isolation. A modified “overlay” solid medium was devised and used to isolate this bacterium from a number of mine water samples. The physiological and phylogenetic characteristics of a pure culture of an isolate from an abandoned copper mine (“Ferrovum myxofaciens” strain P3G) have been elucidated. “F. myxofaciens” is an extremely acidophilic, psychrotolerant obligate autotroph that appears to use only ferrous iron as an electron donor and oxygen as an electron acceptor. It appears to use the Calvin-Benson-Bassham pathway to fix CO₂ and is diazotrophic. It also produces copious amounts of extracellular polymeric materials that cause cells to attach to each other (and to form small streamer-like growth in vitro) and to different solid surfaces. “F. myxofaciens” can catalyze the oxidative dissolution of pyrite and, like many other acidophiles, is tolerant of many (cationic) transition metals. “F. myxofaciens” and related clone sequences form a monophyletic group within the Betaproteobacteria distantly related to classified orders, with genera of the family Nitrosomonadaceae (lithoautotrophic, ammonium-oxidizing neutrophiles) as the closest relatives. On the basis of the phylogenetic and phenotypic differences of “F. myxofaciens” and other Betaproteobacteria, a new family, “Ferrovaceae,” and order, “Ferrovales,” within the class Betaproteobacteria are proposed. “F. myxofaciens” is the first extreme acidophile to be described in the class Betaproteobacteria.     

Microbial Communication,Cooperation and Cheating: Quorum Sensing Drives the Evolution of Cooperation in Bacteria

An increasing body of empirical evidence suggests that cooperation among clone-mates is common in bacteria. Bacterial cooperation may take the form of the excretion of “public goods”: exoproducts such as virulence factors, exoenzymes or components of the matrix in biofilms, to yield significant benefit for individuals joining in the common effort of producing them. Supposedly in order to spare unnecessary costs when the population is too sparse to supply the sufficient exoproduct level, many bacteria have evolved a simple chemical communication system called quorum sensing (QS), to “measure” the population density of clone-mates in their close neighborhood. Cooperation genes are expressed only above a threshold rate of QS signal molecule re-capture, i.e., above the local quorum of cooperators. The cooperative population is exposed to exploitation by cheaters, i.e., mutants who contribute less or nil to the effort but fully enjoy the benefits of cooperation. The communication system is also vulnerable to a different type of cheaters (“Liars”) who may produce the QS signal but not the exoproduct, thus ruining the reliability of the signal. Since there is no reason to assume that such cheaters cannot evolve and invade the populations of honestly signaling cooperators, the empirical fact of the existence of both bacterial cooperation and the associated QS communication system seems puzzling. Using a stochastic cellular automaton approach and allowing mutations in an initially non-cooperating, non-communicating strain we show that both cooperation and the associated communication system can evolve, spread and remain persistent. The QS genes help cooperative behavior to invade the population, and vice versa; cooperation and communication might have evolved synergistically in bacteria. Moreover, in good agreement with the empirical data recently available, this synergism opens up a remarkably rich repertoire of social interactions in which cheating and exploitation are commonplace.     

Higher Landing Accuracy in Expert Pilots is Associated with Lower Activity in the Caudate Nucleus

The most common lethal accidents in General Aviation are caused by improperly executed landing approaches in which a pilot descends below the minimum safe altitude without proper visual references. To understand how expertise might reduce such erroneous decision-making, we examined relevant neural processes in pilots performing a simulated landing approach inside a functional MRI scanner. Pilots (aged 20–66) were asked to “fly” a series of simulated “cockpit view” instrument landing scenarios in an MRI scanner. The scenarios were either high risk (heavy fog–legally unsafe to land) or low risk (medium fog–legally safe to land). Pilots with one of two levels of expertise participated: Moderate Expertise (Instrument Flight Rules pilots, n = 8) or High Expertise (Certified Instrument Flight Instructors or Air-Transport Pilots, n = 12). High Expertise pilots were more accurate than Moderate Expertise pilots in making a “land” versus “do not land” decision (CFII: d′ = 3.62±2.52; IFR: d′ = 0.98±1.04; p<.01). Brain activity in bilateral caudate nucleus was examined for main effects of expertise during a “land” versus “do not land” decision with the no-decision control condition modeled as baseline. In making landing decisions, High Expertise pilots showed lower activation in the bilateral caudate nucleus (0.97±0.80) compared to Moderate Expertise pilots (1.91±1.16) (p<.05). These findings provide evidence for increased “neural efficiency” in High Expertise pilots relative to Moderate Expertise pilots. During an instrument approach the pilot is engaged in detailed examination of flight instruments while monitoring certain visual references for making landing decisions. The caudate nucleus regulates saccade eye control of gaze, the brain area where the “expertise” effect was observed. These data provide evidence that performing “real world” aviation tasks in an fMRI provide objective data regarding the relative expertise of pilots and brain regions involved in it.     

Nitrous Oxide Inhalation as a Fad—Dangers in Uncontrolled Sniffing for Psychedelic Effect

“LAUGHING GAS is the newest thing for kids seeking kicks,” the Stanford Daily reports. “They sniff it.”So begins a news story in the Los Angeles Times of 26 January 1967. The story continues:“It''s the latest way to travel, or so say a growing group of devotees on the campus,” the university student paper said. “It can produce much the same effects as psychedelic drugs, they claim, and it''s cheaper to obtain.”“One student said he buys the gas, nitrous oxide, from a medical supply house. `They think I am anesthetizing rats,'' he explained.“Campus medical authorities said the gas, sniffed `in sufficient amounts... could produce all the states of anesthesia, including the final stage—death.''”     

Assessment of Survival and Body Size Variation of Culicoides imicola (Diptera: Ceratopogonidae) as Functions of “Candidatus Cardinium” (Bacteroidetes) Infection Status

“Candidatus Cardinium hertigii” (Bacteroidetes) is a maternally inherited endosymbiont known from several arthropods. Its mechanisms for persistence in host populations are mostly reproductive manipulation, though it has been occasionally reported to improve fitness parameters in several hosts. In Culicoides (Diptera: Ceratopogonidae) biting midges, the prevalence of “Candidatus Cardinium” infection was documented as moderate, with no detectable sex bias. We therefore investigated whether “Candidatus Cardinium” affects important fitness parameters, such as survival and body size, in Culicoides imicola, a dominant vector species. Field-collected midges were trapped and analyzed for survival under different environmental conditions and antibiotic treatment, taking into account “Candidatus Cardinium” infection status and parity status (i.e., parous or nulliparous). Additionally, wing lengths were measured as a proxy parameter for body size and analyzed together with “Candidatus Cardinium” infection data. The findings revealed no difference in survival of Culicoides infected with “Candidatus Cardinium” and that of uninfected midges in both parity states and under all tested conditions: optimal, starvation, heat, and antibiotic treatment. Beyond survival, no wing length difference was found for “Candidatus Cardinium”-infected versus uninfected midges. In aggregate, these findings support our conclusion that “Candidatus Cardinium” does not have an overt effect on the survival and size of adult C. imicola midges. “Candidatus Cardinium” may affect immature stages or may alter adult reproductive performance.     

Characterization of Chlorinated Aliphatic Hydrocarbons and Environmental Variables in a Shallow Groundwater in Shanghai Using Kriging Interpolation and Multifactorial Analysis

CAHs, as a cleaning solvent, widely contaminated shallow groundwater with the development of manufacturing in China''s Yangtze River Delta. This study focused on the distribution of CAHs, and correlations between CAHs and environmental variables in a shallow groundwater in Shanghai, using kriging interpolation and multifactorial analysis. The results showed that the overall CAHs plume area (above DIV) was approximately 9,000 m² and located in the 2–4 m underground, DNAPL was accumulated at an area of approximately 1,400 m² and located in the 6-8m sandy silt layer on the top of the muddy silty clay. Heatmap of PPC for CAHs and environmental variables showed that the correlation between “Fe²⁺” and most CAHs such as “1,1,1-TCA”, “1,1-DCA”, “1,1-DCE” and “%TCA” were significantly positive (p<0.001), but “%CA” and/or “%VC” was not, and “Cl^-” was significantly positive correlated with “1,1-DCA” and “1,1-DCE” (p<0.001). The PCA demonstrated that the relative proportions of CAHs in groundwater were mostly controlled by the sources and the natural attenuation. In conclusion, the combination of geographical and chemometrics was helpful to establishing an aerial perspective of CAHs and identifying reasons for the accumulation of toxic dechlorination intermediates, and could become a useful tool for characterizing contaminated sites in general.