Calcium isotopic composition of high-latitude proxy carrier Neogloboquadrina pachyderma (sin.)

The accurate reconstruction of sea surface temperature (SST) history in climate-sensitive regions (e.g. tropical and polar oceans) became a challenging task in palaeoceanographic research. Biogenic shell carbonate SST proxies successfully developed for tropical regions often fail in cool water environments. Their major regional shortcomings and the cryptic diversity now found within the major high latitude proxy carrier Neogloboquadrina pachyderma (sin.) highlight an urgent need to explore complementary SST proxies for these cool-water regions. Here we incorporate the genetic component into a calibration study of a new SST proxy for the high latitudes. We found that the calcium isotopic composition (δ44/40Ca) of calcite from genotyped net catches and core-top samples of the planktonic foraminifera Neogloboquadrina pachyderma (sin.) is related to temperature and unaffected by genetic variations. The temperature sensitivity has been found to be 0.17 (±0.02)‰ per 1°C, highlighting its potential for downcore applications in open marine cool-water environments. Our results further indicate that in extreme polar environments, below a critical threshold temperature of 2.0 (±0.5)°C associated with salinities below 33.0 (±0.5)‰, a prominent shift in biomineralization affects the δ44/40Ca of genotyped and core-top N. pachyderma (sin.), becoming insensitive to temperature. These findings highlight the need of more systematic calibration studies on single planktonic foraminiferal species in order to unravel species-specific factors influencing the temperature sensitivity of Ca isotope fractionation and to validate the proxies' applicability

Seasonal distribution of genetic types of planktonic foraminifer morphospecies in the Santa Barbara Channel and its paleoceanographic implications

We present data on the temporal distribution of planktonic foraminifer genotypes (small subunit (SSU) ribosomal (r) RNA gene) and morphospecies (sediment traps) collected during 1999 in the Santa Barbara Channel. The sampling was undertaken with special emphasis on paleoceanographically important morphospecies, predominantly Globigerina bulloides. We found the same genotype of G. bulloides (type IId) in all the changing hydrographic regimes associated with this region throughout the annual cycle with the exception of January, when we recorded the additional presence of the high-latitude G. bulloides type IIa. We identified three new genotypes: Neogloboquadrina dutertrei type Ic, N. pachyderma dextral type II, and Turborotalita quinqueloba type IId. Our data suggest that G. bulloides type IId and possibly even the new genotypes listed above may be associated specifically with the complex hydrography or other environmental features characteristic of this area. Since G. bulloides type IId occurs throughout the year and its peak fluxes are related to different hydrographic regimes, we argue that the physical properties of the water column are not the major factor influencing the distribution and growth of this genotype. In sediment trap samples we found a skewed coiling ratio for G. bulloides (most likely representing type IId), which is related neither to sea surface temperature nor to genotypic difference. This study illustrates the necessity to map both the spatial and temporal distribution of the genetic types, especially in areas of paleoceanographic interest, where geochemical and paleontological proxies are being calibrated

The Economic Impacts of the Regional Greenhouse Gas Initiative on Ten Northeast and Mid-Atlantic States

Assesses outcomes of the first U.S. market-based program to reduce emissions of carbon dioxide from power plants, including impact on electricity markets, power companies' costs, and consumer prices; use of auction proceeds; and states' economic benefits

Ecological partitioning and diversity in tropical planktonic foraminifera

Background: Ecological processes are increasingly being viewed as an important mode of diversification in the marine environment, where the high dispersal potential of pelagic organisms, and a lack of absolute barriers to gene flow may limit the occurrence of allopatric speciation through vicariance. Here we focus on the potential role of ecological partitioning in the diversification of a widely distributed group of marine protists, the planktonic foraminifera. Sampling was conducted in the tropical Arabian Sea, during the southwest (summer) monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses. Results: We uncovered extensive genetic diversity within the Arabian Sea planktonic foraminifera, identifying 13 morphospecies, represented by 20 distinct SSU rRNA genetic types. Several morphospecies/genetic types displayed non-random biogeographical distributions, partitioning between the northern and southern water masses, giving a strong indication of independent ecological adaptations. Conclusions: We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed. Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms

The role of lattice parameter in water adsorption and wetting of a solid surface

Reducing the lattice parameter of a Sn–metal surface alloy below the O–O separation of ice disrupts the flat wetting layer, causing the first layer to buckle and instead form ice clusters.</p

Elastic and thermodynamic properties of the shape-memory alloy AuZn

The current work reports on the elastic shear moduli, internal friction, and the specific heat of the B2 cubic ordered alloy AuZn as a function of temperature. Measurements were made on single-crystal and polycrystalline samples using Resonant Ultrasound Spectroscopy (RUS), semi-adiabatic calorimetry and stress-strain measurements. Our results confirm that this alloy exhibits the shape-memory effect and a phase transition at 64.75 K that appears to be continuous (second-order) from the specific heat data. It is argued that the combination of equiatomic composition and a low transformation temperature constrain the chemical potential and its derivatives to exhibit behavior that lies at the borderline between that of a first-order (discontinuous) and a continuous phase transition. The acoustic dissipation does not peak at the transtion temperature as expected, but shows a maximum well into the low-temperature phase. The Debye temeprature value of 219 K, obtained from the low-temperature specific heat data is in favorable agreement with that determined from the acoustic data (207 K) above the transition.Comment: 25 pages, 6 figures, submitted to Phys. Rev.

Influences on the implementation of a physiological care approach: A mixed methods study in two obstetric units

Routine clinical intervention use in labour and birth is evidenced to cause harm. To under-stand continuing increases and wide variations in its use, this thesis presents the findings of original research that explored influences on implementing a physiological care approach. In a physiological care approach, care focuses on meeting the woman’s physical and emotional needs, while clinical intervention is used during labour and birth, only when problems that arise warrant it. The location was two obstetric units where clinical intervention rates are evidenced to be higher than other birth settings. Aim: To explore and understand influences on the implementation of a physiological care approach in two obstetric units. Design: An embedded mixed method explanatory study underpinned by Dewey’s Pragmatism. Sample: This comprised of two consultant midwives and two obstetricians, 12 women and their birth partners who experienced care during labour and birth, and 16 midwives who provided their care. Methods: Observations and interviews were used. In observations, data was gathered on the midwives’ training; their use of physiological care practices; and decision-making by mid-wives and obstetricians during labour. Interviews explored participants’ experiences of driving; implementing a physiological care approach; and receiving care. Familiarisation with a care guideline was undertaken. Three stages of analysis included (i) a descriptive quantitative analysis of use of physiological care practices; (ii) a thematic analysis of observations of practices, training and interviews; (iii) an integrated analysis of quantitative and qualitative findings. Findings: Organisational leadership: An important facilitator was the committed leadership of two consultant midwives who collaborated with two consultant obstetricians. However, consultant midwives were of the view that resourcing decisions to prioritise an obstetric framework of care, and resistance to a physiological care approach, acted as a barrier. Professional Groups: Observation and midwives’ experiences predominantly identified the use of hierarchical decision-making and centralised surveillance to embed an interventionist approach. Midwives’ use of physiological care practices was observed to be variable. The routine use of an interventionist approach was engendered by large workloads, risk preoccupations and lack of skills to facilitate or provide consistent support for implementing a physiological care approach. However, the norm of an interventionist approach was also observed and experienced as a preference amongst most professionals in the OUs including midwives. Women: Women, with the support of their partners, sought to experience a physiological labour and birth but were not fully supported. Midwives assumed women who used OUs were open to clinical intervention, and routinely offered it to them. There was a lack of advocacy, options for care were not always explored, and informed consent was not always obtained for clinical interventions. Conclusion: While there were facilitating influences, barriers predominated at all levels, negatively influencing the implementation of a physiological care approach. Recommendations: A greater understanding of the need to prioritise and resource projects to progress implementation of physiological care approach; increased opportunities to develop skills including provision of clinical support; appraisal work to foster collaborative working between midwives and obstetricians; enhancing women’s understanding of choices to experience a physiological birth; respecting women’s choices, including advocating on women’s behalf during labour can facilitate implementation in OUs