Search

A 492‐year‐long, continuous δ18O time series from a massive Poritescoral colony in Ta'u, American Samoa, records contrasting responses to different types of El Niño‐Southern Oscillation (ENSO) through a mixed sea surface temperature and salinity signal. Currently, conventional El Niño (La Niña) events generate cold and salty (warm and fresh) anomalies at Ta'u, while Modoki El Niño (La Niña) events warm (cool) the waters at Ta'u. Over the course of the twentieth century, the Ta'u δ18O record underwent a polarity shift in its response to conventional ENSO: A warm and fresh (cool and salty) response to El Niño (La Niña) was replaced by the opposite pattern. We interpret this as evidence for the movement of the Eastern Pacific ENSO null zone, the narrow band of the surface ocean where sea surface temperature variability is not on average correlated with ENSO. This movement appears to be related to overall shrinking of the ENSO footprint over the twentieth century. We infer no such trend in the Modoki footprint. The five‐century‐long Ta'u record shows dramatic, century‐scale changes in ENSO‐band variability. Comparisons with other ENSO reconstructions lead to conflicting interpretations: The Ta'u coral may have recorded changes in the strength of ENSO or in its spatial footprint. Changes in the spatial footprint manifest as a changing sensitivity to ENSO at any given location, presenting challenges to established methods of ENSO reconstruction. Coral oxygen isotope data from American Samoa record contrasting responses to different types of ENSOThe Eastern Pacific ENSO null (zero‐correlation) zone has shifted northeast in the twentieth century, shrinking ENSO's footprintChanges in the spatial patterns of ENSO complicate the interpretation of ENSO proxies

Continuous stable isotope records from marine sediment cores spanning the Pliocene have been used to assess the oceans' response to major perturbations in the climate system as the oceans play an integral role in regulating the global distribution of heat and gases. The Early to mid‐Pliocene has previously been characterized as a time of relative warmth followed by Late Pliocene Southern Hemisphere cooling and bipolar glaciation at ~2.7 Ma. Previous studies have predominantly focused on the Atlantic and Equatorial Pacific Oceans. In this study, we extended the deep water benthic foraminifera stable isotope record from Ocean Drilling Program (ODP) Site 1123 in the southwest Pacific, back to the warm Early Pliocene. This is a high‐latitude site at the gateway where the abyssal waters enter the Pacific Ocean and provides information about the connection between the Southern Ocean and the Pacific. We identify a dichotomy between the deep southwest Pacific and South Atlantic δ13C records spanning the mid‐Pliocene and suggest that this is most likely the result of variations in the relative contributions of Northern versus Southern Hemisphere deep waters to the different basins. At 3.6 Ma, δ13C values start to decrease; this is interpreted to represent alteration in preformed values as a result of increased remineralization of carbon caused by a reduction in deep ocean ventilation in the Southern Ocean. This is likely the consequence of a greater extent and seasonal duration of sea ice in the Southern Ocean from Antarctic Ice Sheet expansion and cooling. We present the Early to mid‐Pliocene benthic foraminiferal stable isotope record from the SW PacificComparison to global data sets implies deep connection between the Southern Ocean and Pacific Ocean circulation during the PlioceneWe identify three major time steps 3.6, 2.7, and 1.5 Ma in which δ13C values imply changes in abyssal circulation

ABSTRACTI argue that three questions are invariably overlooked in the study of religion: (1) why religions, and particularly shamanic-type religions, evolved, (2) why doctrinal religions evolved a mere 8000 years ago, and (3) why only humans have religion.

Trace elemental ratios preserved in the calcitic skeleton of bamboo corals have been shown to serve as archives of past ocean conditions. The concentration of dissolved barium (BaSW), a bioactive nutrientlike element, is linked to biogeochemical processes such as the cycling and export of nutrients. Recent work has calibrated bamboo coral Ba/Ca, a new BaSWproxy, using corals spanning the oxygen minimum zone beneath the California Current System. However, it was previously unclear whether Ba/Cacoralrecords were internally reproducible. Here we investigate the accuracy of using laser ablation inductively coupled plasma mass spectrometry for Ba/Cacoralanalyses and test the internal reproducibility of Ba/Ca among replicate radial transects in the calcite of nine bamboo corals collected from the Gulf of Alaska (643–720 m) and the California margin (870–2054 m). Data from replicate Ba/Ca transects were aligned using visible growth bands to account for nonconcentric growth; smoothed data were reproducible within ~4% for eight corals (n= 3 radii/coral). This intracoral reproducibility further validates using bamboo coral Ba/Ca for BaSWreconstructions. Sections of the Ba/Ca records that were potentially influenced by noncarbonate bound Ba phases occurred in regions where elevated Mg/Ca or Pb/Ca and coincided with anomalous regions on photomicrographs. After removing these regions of the records, increased Ba/Cacoralvariability was evident in corals between ~800 and 1500 m. These findings support additional proxy validation to understand BaSWvariability on interannual timescales, which could lead to new insights into deep sea biogeochemistry over the past several centuries. Agreement between solution phase ICP‐MS and LA‐ICP‐MS shows the accuracy of using NIST 612 glass to measure bamboo coral Ba/Ca via LA‐ICP‐MSHigh intracoral reproducibility demonstrated in skeletal Ba/Ca records from eight bamboo coral calcite samplesInterannual‐decadal scale Ba/Ca variability in NE Pacific corals may provide insights into changes in intermediate ocean biogeochemistry

SMAP (Soil Moisture Active and Passive) radiometer observations at ∼40 km resolution are routinely assimilated into the NASA Catchment Land Surface Model to generate the 9 km SMAP Level‐4 Soil Moisture product. This study demonstrates that adding high‐resolution radar observations from Sentinel‐1 to the SMAP assimilation can increase the spatiotemporal accuracy of soil moisture estimates. Radar observations were assimilated either separately from or simultaneously with radiometer observations. Assimilation impact was assessed by comparing 3‐hourly, 9 km surface and root‐zone soil moisture simulations with in situ measurements from 9 km SMAP core validation sites and sparse networks, from May 2015 to December 2016. The Sentinel‐1 assimilation consistently improved surface soil moisture, whereas root‐zone impacts were mostly neutral. Relatively larger improvements were obtained from SMAP assimilation. The joint assimilation of SMAP and Sentinel‐1 observations performed best, demonstrating the complementary value of radar and radiometer observations. Sentinel‐1 radar and SMAP radiometer observations provide complementary information on soil moistureAssimilating Sentinel‐1 and SMAP observations improves the spatiotemporal accuracy of soil moisture estimatesAdding Sentinel‐1 data increases the assimilation impact by up to 30%, relative to that of SMAP‐only assimilation

This research investigated the effects of future climate change on pavement life in South Africa by simulating prolonged moisture presence in the pavement subgrade. The study was conducted on roads P435 and P443 within uMkhanyakude District Municipality. Climatic data were collected from the Council for Scientific and Industrial Research (CSIR) and Climate Systems Analysis Group (CSAG) from 1940 to 2001 and simulated from 2012 to 2062. Sampling was done using the standard procedure described in Technical Methods for Highways (TMH) 5 and soil laboratory tests carried out according to TMH 1. Results of laboratory tests classified the materials as G10 based on their California bearing ratio (CBR) and plasticity index (PI). Relative compaction of 91.4 and 94.3% were obtained from the CBR test on the subgrade layers of roads P435 and P443 respectively. The research showed that 50 years into the future will bring a climate change signal that will be minimal in terms of precipitation. However, natural weather variability threatens to be the dominant signal. The pavement life has been shown to decrease in a way that would threaten the road category and design reliability.

Bicondylar tibial plateau fractures result from high-energy injuries. Fractures of the tibial plateau can involve the tibial tubercle, which represents a disruption to the extensor mechanism and logically must be stabilised. The purpose of this study was to identify the incidence of an independent tibial tubercle fracture in bicondylar tibial plateau fractures, and to report management strategies and potential complications. We retrospectively reviewed a prospectively collected orthopaedic trauma database for the period January 2003 to December 2008, and identified 392 bicondylar fractures of the tibial plateau, in which 85 tibial tubercle fractures (21.6%) were identified in 84 patients. There were 60 men and 24 women in our study group, with a mean age of 45.4 years (18 to 71). In 84 fractures open reduction and internal fixation was undertaken, either with screws alone (23 patients) or with a plate and screws (61 patients). The remaining patient was treated non-operatively. In all, 52 fractures were available for clinical and radiological assessment at a mean follow-up of 58.5 weeks (24 to 94). All fractures of the tibial tubercle united, but 24 of 54 fractures (46%) required a secondary procedure for their tibial plateau fracture. Four patients reported pain arising from prominent tubercle plates and screws, which in one patient required removal. Tibial tubercle fractures occurred in over one-fifth of the bicondylar tibial plateau fractures in our series. Fixation is necessary and can be reliably performed with screws alone or with a screw and plate, which restores the extensor mechanism and facilitates early knee flexion.Cite this article: Bone Joint J2013;95-B:1697–1702.

A Gulf of Mexico performance evaluation and comparison of coastal circulation and wave models was executed through harmonic analyses of tidal simulations, hindcasts of Hurricane Ike (2008) and Rita (2005), and a benchmarking study. Three unstructured coastal circulation models (ADCIRC, FVCOM, and SELFE) validated with similar skill on a new common Gulf scale mesh (ULLR) with identical frictional parameterization and forcing for the tidal validation and hurricane hindcasts. Coupled circulation and wave models, SWAN+ADCIRC and WWMII+SELFE, along with FVCOM loosely coupled with SWAN, also validated with similar skill. NOAA's official operational forecast storm surge model (SLOSH) was implemented on local and Gulf scale meshes with the same wind stress and pressure forcing used by the unstructured models for hindcasts of Ike and Rita. SLOSH's local meshes failed to capture regional processes such as Ike's forerunner and the results from the Gulf scale mesh further suggest shortcomings may be due to a combination of poor mesh resolution, missing internal physics such as tides and nonlinear advection, and SLOSH's internal frictional parameterization. In addition, these models were benchmarked to assess and compare execution speed and scalability for a prototypical operational simulation. It was apparent that a higher number of computational cores are needed for the unstructured models to meet similar operational implementation requirements to SLOSH, and that some of them could benefit from improved parallelization and faster execution speed. ADCIRC, FVCOM, and SELFE perform similarly for tides and storm surgeSLOSH did not simulate storm surge as accurately as unstructured modelsSLOSH is computationally less costly than the unstructured models.

We use data from 20 chimpanzee, bonobo and gorilla study sites to develop an African great ape time budgets model to predict the animals' capacity to survive in a range of habitats across sub-Saharan Africa. The model uses body mass and climatic data to predict the time animals must allocate to key activities (feeding, moving, resting and social interaction), and then uses these to assess the limiting group size that could be sustained in a particular habitat. The model is robust against changes in minimum cut-off values, and predicts the current biogeographic distributions of the two African ape species remarkably well. Predicted group sizes for Pan and Gorilla are close to observed averages. The model also indicates that moving time plays a crucial role for both Pan and Gorilla site presence: i.e. at sites where they are absent it is primarily moving time that is increased as compared to other time budget variables. Finally, the model demonstrates that Pan and Gorilla distributions and group sizes can be accurately modelled by simply modifying the body mass variable, indicating that both share a similar underlying ecological bauplan.

Conversation is a uniquely human phenomenon. Analyses of freely forming conversations indicate that approximately two thirds of conversation time is devoted to social topics, most of which can be given the generic label gossip.This article first explores the origins of gossip as a mechanism for bonding social groups, tracing these origins back to social grooming among primates. It then asks why social gossip in this sense should form so important a component of human interaction and presents evidence to suggest that, aside from servicing social networks, a key function may be related explicitly to controlling free riders. Finally, the author reviews briefly the role of social cognition in facilitating conversations of this kind.

Calculations and comparisons were made for a set of seven metal cations binding to corannulene and coronene, namely, the three alkalis Li⁺, Na⁺, and K⁺ and the four transition-metal ions Ti⁺, Cr⁺, Ni⁺, and Cu⁺ (combined with literature results for Li⁺/corannulene). In the case of corannulene, the most favorable binding site for Ti⁺ and Ni⁺ is η⁶ over the six-membered ring on the convex face, whereas for Li⁺, Na⁺, K⁺, and Cr⁺, the five-membered η⁵ ring site on the convex face is about equally good. Cu⁺ slightly prefers binding at η² edge sites rather than ring-centered sites on corannulene, but edge locations for several other ions were not found to be favored, in contrast to results reported for C60. For the alkalis, binding to the convex (outside) face is slightly favored relative to binding to the concave face, whereas for the transition metals, a much larger preference for outside binding is found, particularly for the η⁵ sites. An approximate point-charge model calculation is used to separate the electrostatic-plus-polarization contributions to the binding to the η⁵ sites from the electronic orbital contributions. Judging from this analysis, electronic orbital interactions favor outside binding of transition-metal ions by amounts ranging from about 5 to 11 kcal mol^-1. A molecular orbital picture is proposed that invokes perturbations of π−d donation and d−π* back-donation to explain the particularly unfavorable electronic binding interaction on the concave π face. Binding to the flat coronene π surface is found to be roughly equal to the outside η⁵ binding sites of the curved corannulene π surface.

Electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry has been utilized to study solvates of tris(2,2‘-bipyridine)ruthenium(II). Spontaneous dissociation of solvent (acetonitrile, acetone, or methyl ethyl ketone) from the solvation shell occurs when these ions are trapped for extended periods of time in the ICR cell. The pressures employed in these experiments are low enough (10^-9 to 10^-8 mbar) to neglect (or partially neglect) collisional activation as a means for dissociation. Therefore, it is suggested that the solvated ruthenium species undergo dissociation following the absorption of blackbody infrared radiation. Solvent−complex dissociation has been studied at several pressures ranging from 10^-9 to 10^-8 mbar to provide a range of dissociation data in the low-pressure regime. The results reported here demonstrate the consistency of the dissociation rate constants at pressures that differ by an order of magnitude. Temperature dependence studies were performed to extract zero-pressure activation energies from Arrhenius analyses. Given the number of degrees of freedom and the magnitude of the rate constants at a given temperature of the ruthenium complex ion solvates, the experimental Arrhenius activation energies are likely to be substantially lower than the true bond dissociation energies. ZINDO semiempirical methods, which were calibrated against DFT and experimental values, have been used to determine optimized structures and vibrational frequencies for bipyridine-containing ruthenium(II) solvates. These parameters were then used both for master equation modeling and the truncated Boltzmann/modified Tolman approach, each of which provide calculated binding energies of the solvents to the ruthenium complex ion. Solvation energies in the range 15−20 kcal/mol were found for binding of solvent molecules in the first solvation shell of tris(2,2‘-bipyridine) ruthenium(II) ions.

The two metal ion binding regions of phenol were characterized and compared by density functional theory (DFT). The monocations of sodium, magnesium, aluminum, and the first-row transition series were considered, using mainly the B3LYP and MPW1PW91 functionals. Calculations on the model ligands water and benzene were carried out at the same level of theory. The MPW1PW91 functional is more favorable than the B3LYP functional toward binding to the aromatic ring, while no strong difference is seen for oxygen binding. Comparison with experimental data and higher level computational results for water and benzene indicate that MPW1PW91 is better than B3LYP in predicting the differential between ring and oxygen binding energies, and seems to do an excellent job of making this comparison. Except for Na⁺, for which the ring and oxygen neighborhoods have similar binding energies, the ring site of phenol was favored for all the metal ions. The differential was quite small (2−3 kcal mol^-1) for Mg⁺, for which the O site may have significant thermal population at ordinary temperatures. Al⁺, Cr⁺, and Mn⁺ showed ring/O differential binding energies of 5−6 kcal mol^-1, which probably rules out significant thermal populations of the oxygen site. The other transition metal ions all showed very large ring/O binding energy differentials. The ring/O binding differentials for phenol were accurately mirrored by the differentials between binding of the same metal ions to benzene versus water.

Abstract: Heroism is apparently nonadaptive in Darwinian terms, so why does it exist at all? Risk-taking and heroic behavior are predominantly male tendencies, and literature and legend reflect this. This study explores the possibility that heroism persists in many human cultures owing to a female preference for risk-prone rather than risk-averse males as sexual partners, and it suggests that such a preference may be exploited as a male mating strategy. It also attempts to quantify the relative influences of altruism and bravery in the evolution of heroism. Our study found that females do prefer risk-prone brave males to risk-averse non-brave males, and that men are aware of this preference. Bravery in a male was shown to be the stronger factor influencing female choice of short-term partners, long-term partners, and male friends, with altruism playing a lesser part in their choice. Altruism was deemed important in long-term relationships and friendships, but for short-term liaisons, non-altruists were preferred to altruists. Heroism may therefore have evolved owing to a female preference for brave, risk-prone males because risk-taking acts as an honest cue for "good genes." Altruism was judged to be a less influential factor in the evolution of heroism than bravery and a demonstrated willingness to take risks.

Binding energies were calculated for the complexes of Na⁺ and K⁺ with phenylalanine (Phe), tyrosine (Tyr), and tryptophane (Trp), along with energies of low-energy conformers of the neutral amino acids. Structures were optimized and energies determined by density functional theory (DFT) with the B3LYP functional, using a basis set of 6-31+g(d) on all, or nearly all, heavy atoms. For all but one cation/ligand system, the most energetically favorable binding geometry was the tridentate N/O/Ring chelate. For K⁺/Trp, however, the advantage of placing the metal ion over the phenyl region of the indole side chain was dominant, leading to a most favored bidentate O/Ring binding geometry. All of the systems, and particularly the Trp systems, have multiple conformers with stabilities within a few kcal mol^-1 of the most stable. Zwitterion forms of the complexes were not unreasonable, but were less stable than the normal forms by ~5 kcal mol^-1. To assess the importance of cation−π interactions, conformers were examined in which the side chain was rotated out of chelation. This indicated cation−π stabilization energies of ~5 kcal mol^-1.

Ab initio calculations using G2 theory and other methods have been performed for the collision complexes of the metal ions Na⁺, Mg⁺, and Al⁺ with the molecules H2, CO, N2, NH3, H2O, HCN, HNC, C2H2, C2H4, c−C3H2, H2CCC, H2CCCC, and HCCCN. Binding energies, vibrational frequencies, and infrared intensities obtained from these calculations have been used to perform variational transition state theory (VTST) calculations for the corresponding radiative association reactions at temperatures pertinent to dense interstellar clouds and the outer regions of circumstellar envelopes. The calculated rate coefficients for radiative association reactions with H2 and with the other smaller molecules of this group are slow compared with the chemical evolutionary time scale of cold interstellar clouds. For the largest and most strongly bound complexes considered, the rate of depletion of M⁺ by this mechanism becomes competitive with recombination of M⁺ with free electrons. Predicted rates for association in several systems at high pressure are in order-of-magnitude agreement with experiments, except for Mg⁺/H2O, which is predicted to be substantially faster than a recent experimental upper limit.

The binding energies of M⁺ and MX⁺ ions to benzene and mesitylene were measured by the radiative association kinetics approach in the Fourier transform ion cyclotron resonance (FT-ICR) spectrometer, where M was Mg, Ca, or Sr and X was Cl or Br. MCl⁺ binds to the aromatic face roughly half again as strongly as the corresponding M⁺ ion. (For instance, 2.6 eV vs 1.6 eV for MgCl(benzene)⁺ vs Mg(benzene)⁺.) This is true for all three metals, although the absolute magnitude of the binding energy decreases sharply in going from Mg to Ca to Sr as a consequence of decreasing electrostatic interaction. Bromide has a smaller effect on the binding ability of the metal center than chloride, in keeping with its lower electron-withdrawing ability. Quantum chemical calculations for MgCl⁺ are in accord with the measured binding energy and also show the expected decrease of the metal−ring bond distance in going from Mg⁺ to MgCl⁺. The qualitative picture is presented that MX⁺ behaves as a metal ion center with the charge of a monovalent ion but the electronic character of a divalent alkaline earth cation. The calculations indicate that the gas-phase binding of MX⁺ ions to the aromatic face is intermediate between the binding abilities of M⁺ and M²⁺. In the particular case of MgCl⁺, quantitative analysis via quantum chemical calculations indicates that this ion binds in a manner equivalent to a hypothetical magnesium center with fractional charge of +1.3 to +1.4. A second aromatic ligand normally adds to the monomer complex. Radiative association kinetics analysis indicates that the second ligand is bound with energy comparable to, or somewhat less than, the first ligand, and substantially less in the magnesium cases.

This paper explores the reputations of 63 German firms over the period 1988 to 1998. It considers what factors may affect firm reputations and how and why reputations change. The reputation data come from the survey by Manager Magazinthat is similar to the one compiled annually by Fortunemagazine in the USA. The results show that firm reputations fluctuate reflecting: — firm efforts to improve their reputation, and — critical news reports and specific negative incidents diminishing firm reputation. While industry effects limit fluctuations in corporate reputation, the data also demonstrate firm level differences. Detailed analysis of the relationship between reputation and a measure of financial performance suggests that, in these data, prior financial performance has a strong effect on subsequent reputation. In turn, reputation appears more weakly related to a measure of subsequent financial performance. Finally, larger firm size and more concentrated ownership also lead managers to ascribe better reputations to German firms.

Binding energies to pyrrole were determined for a number of main-group and transition-metal cations (both monomer complexes with one pyrrole ligand and dimer complexes with two ligands). Experimental data were obtained by radiative association kinetics measurements in the Fourier transform ion cyclotron resonance ion trapping mass spectrometer, along with ligand exchange equilibrium determinations (for the Mg⁺ and Al⁺ cases) using benzene as the reference ligand. Density functional calculations using the B3LYP hybrid functional were carried out on all complexes. The calculations indicated binding only to the π site of pyrrole, with no significantly stable binding site being found for binding of any metal ion in the vicinity of the nitrogen. Experimental binding energies for the transition-metal monomer complexes were parallel to previously reported benzene values. Mg⁺ and Al⁺ were more strongly bound to pyrrole than benzene, presumably due to the dipole moment of pyrrole. The quantum chemical binding energy values for the monomers were reasonably parallel to the experimental values, but were generally lower by a few kcal/mol. For the dimer complexes, the experimental and quantum chemical values were in satisfactory agreement. The pyrrole transition-metal dimers contrasted strongly with the trend previously reported for the corresponding benzene dimers, showing relatively weaker binding for the early transition metals falling to a minimum at Mn⁺, rising sharply for the later transition metals, and dipping again for Cu⁺.

Abstract: This study investigated the use of mobile telephones by males and females in a public bar frequented by professional people. We found that, unlike women, men who possess mobile telephones more often publicly display them, and that these displays were related to the number of men in a social group, but not the number of women. This result was not due simply to a greater number of males who have telephones: we found an increase with male social group size in the proportion of available telephones that were on display. Similarly, there was a positive relationship between the number of visible telephones and the ratio of males to females. Our results further show that the increased display of telephones in groups with more males is not due to the ostensive function of these devices (i.e., the making and receiving of calls), although single males tended to use their phones more. We interpret these results within the framework of male-male competition, with males in larger group sizes functioning in an increasingly competitive environment. This competitive environment is suggested to be akin to a lek mating system in which males aggregate and actively display their qualities to females who assess males on a number of dimensions. We suggest that mobile telephones might be used by males as an indicator of their status and wealth (sensu “cultural ornaments”).

Coral reefs are hydrodynamically rough, creating turbulent boundary layers that transport and mix various scalars that impact reef processes and also can be used to monitor reef health. Often reef boundary layer characteristics derived from a single instrument are assumed to accurately represent the study site. This approach relies on two assumptions: first, that the boundary layer is relatively homogeneous across the area of interest, and second, that two instruments displaced in space or with different spatiotemporal resolution would produce similar results when sampling the same flow. We deployed four velocimeters over a 15 × 20 m reef at 10 m depth in the Chagos Archipelago. The site had a 1 m tidal range, and waves were primarily locally generated wind waves with Hrms< 0.5 m. Depth‐averaged currents were typically 0.2 m/s. Friction velocities derived directly from Reynolds stress measurements by fitting the law of the wall show agreement between instruments (pairwise coefficients of determination R2ranged from 0.53 to 0.86). Thus, the boundary layer appears to be spatially homogeneous, at least at the scale of our array, and it appears that in the present case friction velocities from one instrument are indeed generally representative of the site. We calculate drag coefficients using curve‐fitting and Structure‐from‐Motion photogrammetry, and while we find general agreement between estimates one instrument in particular produces drag coefficients an order of magnitude larger in comparison. Hence, some variability between instruments was observed, notably when high‐resolution instruments measured localized flow features. Coral reefs are characterized by variable bottom features at scales from small coral polyps to rocky substrates and large bommies. This variability is often present on scales of centimeters to tens of meters. However, scientists seldom have enough resources in terms of time and equipment to fully instrument reefs to capture this variability, and often rely on assumptions that their measurements are representative of a larger area while sampling a small subset. One feature of particular interest is the boundary layer, the bottom part of the water column where the current interacts with the corals. Understanding the boundary layer allows scientists to infer a wealth of information, including reef metabolism and input parameters for computer models. In this study, we placed four instruments using different measurement approaches over a 15 × 2 m area of a reef in the Indian Ocean to test whether estimates of the flow were comparable when measured at different locations with different instruments. Estimates agreed overall on the flow characteristics, except from instruments measuring localized flow features close to the corals. Thus, our results offer support to the often implied assumption that we can capture important flow parameters on coral reefs in spite of limited resources. Due to resource limitations, friction velocities and drag coefficients are often based on a single instrumentObservations show correlation of friction velocities from four velocimeters of varying spatiotemporal resolution deployed on the same reefWe compare drag coefficients calculated using curve‐fitting and photogrammetry, which yield lower correlation due to localized flow features Due to resource limitations, friction velocities and drag coefficients are often based on a single instrument Observations show correlation of friction velocities from four velocimeters of varying spatiotemporal resolution deployed on the same reef We compare drag coefficients calculated using curve‐fitting and photogrammetry, which yield lower correlation due to localized flow features

Mate choice strategies are a process of negotiation in which individuals make bids that are constrained by their status in the market place. Humans provide an unusual perspective on this because we can measure their explicitly expressed preferences before they are forced to make any choices. We use advertisements placed in newspaper personal columns to examine, first, the extent to which evolutionary considerations affect the level of competition (or market value) during the reproductively active period of people's lives and, second, the extent to which market value influences individual's willingness to make strong demands of prospective mates. We show that female market value is determined principally by women's fecundity (and, to a lesser extent, reproductive value), while male market value is determined by men's earning potential and the risk of future pairbond termination (the conjoint probability that the male will either die or divorce his partner during the next 20 years). We then show that these selection preferences strongly influence the levels of demands that men and women make of prospective partners (although older males tend to overestimate their market value).

Many mechanisms have been proposed to explain why immune responses against human tumor antigens are generally ineffective. For example, tumor cells have been shown to develop active immune evasion mechanisms. Another possibility is that tumor antigens are unable to optimally stimulate tumor-specific T cells. In this study we have used HLA-A2/Melan-A peptide tetramers to directly isolate antigen-specific CD8⁺ T cells from tumor-infiltrated lymph nodes. This allowed us to quantify the activation requirements of a representative polyclonal yet monospecific tumor-reactive T cell population. The results obtained from quantitative assays of intracellular Ca²⁺ mobilization, TCR down-regulation, cytokine production and induction of effector cell differentiation indicate that the naturally produced Melan-A peptides are weak agonists and are clearly suboptimal for T cell activation. In contrast, optimal T cell activation was obtained by stimulation with recently defined peptide analogues. These findings provide a molecular basis for the low immunogenicity of tumor cells and suggest that patient immunization with full agonist peptide analogues may be essential for stimulation and maintenance of anti-tumor T cell responses in vivo.

Many mechanisms have been proposed to explain why immune responses against human tumor antigens are generally ineffective. For example, tumor cells have been shown to develop active immune evasion mechanisms. Another possibility is that tumor antigens are unable to optimally stimulate tumor-specific T cells. In this study we have used HLA-A2/Melan-A peptide tetramers to directly isolate antigen-specific CD8(+) T cells from tumor-infiltrated lymph nodes. This allowed us to quantify the activation requirements of a representative polyclonal yet monospecific tumor-reactive T cell population. The results obtained from quantitative assays of intracellular Ca(2+) mobilization, TCR down-regulation, cytokine production and induction of effector cell differentiation indicate that the naturally produced Melan-A peptides are weak agonists and are clearly suboptimal for T cell activation. In contrast, optimal T cell activation was obtained by stimulation with recently defined peptide analogues. These findings provide a molecular basis for the low immunogenicity of tumor cells and suggest that patient immunization with full agonist peptide analogues may be essential for stimulation and maintenance of anti-tumor T cell responses in vivo.

Novel form of spreading acidification and depression in the cerebellar cortex demonstrated by neutral red optical imaging. A novel form of spreading acidification and depression in the rat cerebellar cortex was imaged in vivo using the pH-sensitive dye, Neutral red. Surface stimulation evoked an initial beam of increased fluorescence (i.e., decreased pH) that spread rostrally and caudally across the folium and into neighboring folia. A transient but marked suppression in the excitability of the parallel fiber-Purkinje cell circuitry accompanied the spread. Characteristics differentiating this phenomenon from the spreading depression of Leao include: high speed of propagation on the surface (average of 450 μm/s), stable extracellular DC potential, no change in blood vessel diameter, and repeatability at short intervals. This propagating acidification constitutes a previously unknown class of neuronal processing in the cerebellar cortex.

Social group size has been shown to correlate with neocortex size in primates. Here we use comparative analyses to show that social group size is independently correlated with the size of nonV1 neocortical areas, but not with other more proximate components of the visual system or with brain systems associated with emotional cueing (e.g. the amygdala). We argue that visual brain components serve as a social information ‘input device’ for socio–visual stimuli such as facial expressions, bodily gestures and visual status markers, while the nonvisual neocortex serves as a ‘processing device’ whereby these social cues are encoded, interpreted and associated with stored information. However, the second appears to have greater overall importance because the size of the V1 visual area appears to reach an asymptotic size beyond which visual acuity and pattern recognition may not improve significantly. This is especially true of the great ape clade (including humans), that is known to use more sophisticated social cognitive strategies.

Hungarian Gypsy populations invest more heavily in daughters than in sons compared to co–resident Hungarians, in conformity with the predictions of the Trivers–Willard hypothesis. These effects are shown for four different measures of parental investment (sex ratio at birth, frequency of abortion, duration of breast–feeding and length of education). Opportunities for hypergamy into the wealthier Hungarian population appears to be one factor causing Gypsies to prefer daughters over sons. We show that differential investment by sex of offspring is directly related to the fitness pay–offs that accrue for each population through both sexes of offspring.

Association reactions of Cd⁺ with benzene and of Ag⁺ with acetone and several unsaturated hydrocarbons were observed in the Fourier-transform ion cyclotron resonance (FT-ICR) spectrometer. The reactions were presumed to occur by radiative association (RA) involving infrared photon emission, and the kinetics were analyzed to derive bond strengths for the ion−neutral complexes. To supply the structures, infrared frequencies, and infrared intensities required for this analysis, ab initio calculations at the Hartree−Fock (HF) and second-order Moeller−Plesset perturbation theory (MP2) levels were carried out for the reactants and the association complexes, and the results are reported. The RA kinetics analysis yielded values for the binding energies of 1.41 ± 0.2 eV for Cd⁺(benzene), 1.68 ± 0.2 eV for Ag⁺(benzene), 1.66 ± 0.2 eV for Ag⁺(acetone), 1.70 ± 0.2 eV for Ag⁺(isoprene), and 1.71 ± 0.2 eV for Ag⁺(2-pentene). The MP2-derived modeling gave higher (and more reliable) binding energies than the HF-derived modeling, but the HF-level modeling was found to provide estimates of useful precision, except for the Ag⁺(benzene) case. Binding energies were also estimated for the observed Ag⁺L2 complexes, and within experimental and modeling error the second ligand was found to bind with the same energy as the first. Clustering of six or more acetaldehydes with Ag⁺ was observed, but it was considered most likely that this reflected fast association with low-abundance polymeric impurities in the acetaldehyde sample.

Data on the number of adults that an individual contacts at least once a month in a set of British populations yield estimates of network sizes that correspond closely to those of the typical “sympathy group” size in humans. Men and women do not differ in their total network size, but women have more females and more kin in their networks than men do. Kin account for a significantly higher proportion of network members than would be expected by chance. The number of kin in the network increases in proportion to the size of the family; as a result, people from large families have proportionately fewer non-kin in their networks, suggesting that there is either a time constraint or a cognitive constraint on network size. A small inner clique of the network functions as a support group from whom an individual is particularly likely to seek advice or assistance in time of need. Kin do not account for a significantly higher proportion of the support clique than they do for the wider network of regular social contacts for either men or women, but each sex exhibits a strong preference for members of their own sex.

Data from various settings suggest that there is an upper limit of about four on the number of individuals who can interact in spontaneous conversation. This limit appears to be a consequence of the mechanisms of speech production and detection. There appear to be no differences between men and women in this respect, other than those introduced by women’s lighter voices.

A family reconstitution study of the Krummhörn population (Ostfriesland, Germany, 1720–1874) reveals that infant mortality and children’s probabilities of marrying or emigrating unmarried are affected by the number of living same-sexed sibs in farmers’ families but not in the families of landless laborers. We interpret these results in terms of a “local resource competition” model in which resource-holding families are obliged to manipulate the reproductive future of their offspring. In contrast, families that lack resources have no need to manipulate their offspring and are more likely to benefit from allowing their offspring to capitalize on whatever opportunities to reproduce present themselves.

Abstract: Two alternative theories have been proposed to explain why some male primates carry infants during agonistic encounters with other males. The first (agonistic buffering) suggests that males carry the infants of higher ranking opponents in order to defuse the latter's aggression; the second (progeny protection) suggests that males carry their own infants as a warning to opponents that they will be prepared to fight vigorously in order to protect their offspring from injury. Evidence is presented to show that both occur in gelada baboons under different circumstances and that, in addition, infant-use may in at least some cases involve indirect solicitation of support from a third party (normally the infant's mother).

Abstract: This paper aims to clarify terminological differences that have arisen between two different field studies of gelada baboons (Theropithecus gelada). First, a comparison of age classifications is made to show the physical correspondences between the two sets of classes. Second, the social system of the gelada baboon is outlined and the terms used to refer to the components of this system are defined and clarified. Attention is drawn to the complex structure of gelada society and to the relationship between the superficially similar social systems of the gelada and the hamadryas baboon.

Abstract: Analyses of data from field studies of baboons (genusPapio) show that observers tend to select the largest groups available to them in their study populations up to a limiting group size of about 80–100 animals. This is likely to introduce significant biasses into eco-correlate analyses whenever group size is an important independent variable.

Abstract: Data are presented on the structure of social relationships in a wild group of gelada baboons (Theropithecus gelada). These data lend support to the deduction from wild populations that female grooming dyads are matrilineal in origin. The observations are discussed in relation to a number of other conclusions on the nature of inter-individual relationships in gelada reproductive units.

A new aerosol-based deposition method, for the production of sol−gel-derived films under ambient conditions, has been developed. Tetraethyl orthosilicate (TEOS) and N-octyltriethoxysilane (TrEOS-C8)-derived sol−gel-processed films were produced using the new technique and compared to films produced by a conventional spin-casting approach. All films were characterized using scanning electron microscopy, profilometry, electron spectroscopy for chemical analysis (ESCA), diffuse-reflectance infrared Fourier transform spectroscopy, and steady-state fluorescence spectroscopy. Sol−gel-derived films produced using the aerosol-based method were uniform, and their thickness could be controlled between 0.6 and at least 3.0 μm. Spin casting of the neat sol−gel-processed solutions generally yielded more thick (2.0 ± 0.10 μm) films, but these thicker films were of poorer optical quality and very often more highly cracked. ESCA data demonstrate surface segregation of the C8 moiety within the TrEOS−C8-derived films. This segregation phenomenon is much more pronounced in the aerosol-generated films. A scenario is proposed where the distribution of and/or the dynamics/solvation of the C8 residue within the aerosol droplet vs the bulk cast film are very different and lead to the segregation. Static fluorescence experiments demonstrate that several dopant classes can be incorporated directly into the sol−gel-processed solution and aerosol deposited. All results are also consistent with films that are heterogeneous on a molecular level. The utility of aerosol-deposited, sol−gel-derived films as a chemical sensing platform is demonstrated using fluorescence quenching of entrapped pyrene by O2.

Observational studies of human conversations in relaxed social settings suggest that these consist predominantly of exchanges of social information (mostly concerning personal relationships and experiences). Most of these exchanges involve information about the speaker or third parties, and very few involve critical comments or the soliciting or giving of advice. Although a policing function may still be important (e.g., for controlling social cheats), it seems that this does not often involve overt criticism of other individuals’ behavior. The few significant differences between the sexes in the proportion of conversation time devoted to particular topics are interpreted as reflecting females’ concerns with networking and males’ concerns with self-display in what amount to a conventional mating lek.

Upon irradiation by a 2.5 kW xenon arc lamp, 1‐ and 2‐butene cations were observed to photodissociate to C2H4+, C3H3+, C3H5+, and C4H7+. An ionic lifetime limiting technique was used with an ICR spectrometer to eliminate largely the effect of ion–molecule reactions on the photofragementation pattern and to obtain quantitative measurements of the relative yields of the various dissociative channels. A unimolecular decay model was found to describe adequately the wavelength dependence of the relative C4H7+ and C3H5+ yields.

Man and environmentThe Rise and Fall of the Third Chimpanzee: How Our Animal Heritage Affects the Way We Live By Jared Diamond Radius, London, 1991, 360pp., £16.99, ISBN 0-09-174268-4.A New World Order By Paul Ekins Routledge, London, 1992, 256pp., £35.00, ISBN 0-415-07114-3 (hbk), £9.99, ISBN 0-415-07115-1 (pbk).A Green History of the World By Clive Ponting. Sinclair-Stevenson, London, 1991, xiv + 432pp., £16.95 (hbk), ISBN 1-85619-050-1; Penguin, London 1992, £6.99 (pbk), ISBN 0-14016-642-4.AlternativesThe Future Belongs to Freedom By Eduard Shevardnadze. Sinclair Stevenson, London, 1991 201pp., £15.00, ISBN 1-85619-105-2.From Arms Race to World Peace: A Review of Attitudes, by Six Scientists Edited by Teresa Belton. Richard Kay, Boston UK 1991 48, pp. £1.95. ISBN 090 2662-91-0 (80 Sleaford Read, Boston, Lincs PE21 8EV).What is Proper Soldiering? By Michael Harbottle. Centre for International Peacebuilding, Chipping Norton, 1991, 30pp, (9 West Street, Chipping Norton, Oxon OX7 5LH).A Future Out of Work?By Paul Quigley Coventry Alternative Employment Research, 1991, 44pp., £2.50 (from CARE, Unit 15, The Arches, Coventry CVI 3JQ)The Gulf WarThe Gulf War and the New World Order Edited by Haim Bresheeth and Nira Yuval-Davis. Zed Books, London, 1991, 272 + xii pp., £32.95 (hbk), ISBN 1-85649-041-6, £11.95 (pbk), ISBN 1-85659-042-4.Disaster PlanningHealth and Medical Aspects of Disaster Preparedness Edited by John C. Duffy. (Volume 14 in the series NATO: Challenges of Modern Society) Plenum Press, New York, 184 + vii pp. price not stated, ISBN 0-306-43495-4.

The radiative association reactions of gas-phase Cr⁺ with benzene and three of its methyl derivatives (toluene, p-xylene, and mesitylene) were studied in the Fourier-transform ion cyclotron resonance ion trap. Sequential formation of the monomer complexes and the sandwich dimer complexes was observed, and the kinetics were analyzed by a recently developed canonical transition-state theory approach to give estimates of the binding energies. The bond strength of Cr⁺−(C6H6) was assigned as 1.70 ± 0.15 eV, and the bond strengths increased slightly with increasing methyl substitution, reaching 2.0 eV for mesitylene. The bond strength for Cr⁺(C6H6)−(C6H6) was assigned as 2.2 ± 0.4 eV, with similar values (within large uncertainties) for the other sandwich complexes. The Cr⁺−(C6H6) value was in good agreement with the value from collision-induced dissociation, and a best value of 1.73 ± 0.10 eV for this bond strength is recommended.