A large West Antarctic Ice Sheet explains early Neogene sea-level amplitude.

Early to Middle Miocene sea-level oscillations of approximately 40-60 m estimated from far-field records1-3 are interpreted to reflect the loss of virtually all East Antarctic ice during peak warmth2. This contrasts with ice-sheet model experiments suggesting most terrestrial ice in East Antarctica was retained even during the warmest intervals of the Middle Miocene4,5. Data and model outputs can be reconciled if a large West Antarctic Ice Sheet (WAIS) existed and expanded across most of the outer continental shelf during the Early Miocene, accounting for maximum ice-sheet volumes. Here we provide the earliest geological evidence proving large WAIS expansions occurred during the Early Miocene (~17.72-17.40 Ma). Geochemical and petrographic data show glacimarine sediments recovered at International Ocean Discovery Program (IODP) Site U1521 in the central Ross Sea derive from West Antarctica, requiring the presence of a WAIS covering most of the Ross Sea continental shelf. Seismic, lithological and palynological data reveal the intermittent proximity of grounded ice to Site U1521. The erosion rate calculated from this sediment package greatly exceeds the long-term mean, implying rapid erosion of West Antarctica. This interval therefore captures a key step in the genesis of a marine-based WAIS and a tipping point in Antarctic ice-sheet evolution.

The amplitude and origin of sea-level variability during the Pliocene epoch.

Earth is heading towards a climate that last existed more than three million years ago (Ma) during the 'mid-Pliocene warm period'1, when atmospheric carbon dioxide concentrations were about 400 parts per million, global sea level oscillated in response to orbital forcing2,3 and peak global-mean sea level (GMSL) may have reached about 20 metres above the present-day value4,5. For sea-level rise of this magnitude, extensive retreat or collapse of the Greenland, West Antarctic and marine-based sectors of the East Antarctic ice sheets is required. Yet the relative amplitude of sea-level variations within glacial-interglacial cycles remains poorly constrained. To address this, we calibrate a theoretical relationship between modern sediment transport by waves and water depth, and then apply the technique to grain size in a continuous 800-metre-thick Pliocene sequence of shallow-marine sediments from Whanganui Basin, New Zealand. Water-depth variations obtained in this way, after corrections for tectonic subsidence, yield cyclic relative sea-level (RSL) variations. Here we show that sea level varied on average by 13 ± 5 metres over glacial-interglacial cycles during the middle-to-late Pliocene (about 3.3-2.5 Ma). The resulting record is independent of the global ice volume proxy3 (as derived from the deep-ocean oxygen isotope record) and sea-level cycles are in phase with 20-thousand-year (kyr) periodic changes in insolation over Antarctica, paced by eccentricity-modulated orbital precession6 between 3.3 and 2.7 Ma. Thereafter, sea-level fluctuations are paced by the 41-kyr period of cycles in Earth's axial tilt as ice sheets stabilize on Antarctica and intensify in the Northern Hemisphere3,6. Strictly, we provide the amplitude of RSL change, rather than absolute GMSL change. However, simulations of RSL change based on glacio-isostatic adjustment show that our record approximates eustatic sea level, defined here as GMSL unregistered to the centre of the Earth. Nonetheless, under conservative assumptions, our estimates limit maximum Pliocene sea-level rise to less than 25 metres and provide new constraints on polar ice-volume variability under the climate conditions predicted for this century.

Antarctic Cenozoic climate history from sedimentary records: ANDRILL and beyond.

Mounting evidence from models and geological data implies that the Antarctic Ice Sheet may behave in an unstable manner and retreat rapidly in response to a warming climate, which is a key factor motivating efforts to improve estimates of Antarctic ice volume contributions to future sea-level rise. Here, we review Antarctic cooling history since peak temperatures of the Middle Eocene Climatic Optimum (approx. 50 Ma) to provide a framework for future initiatives to recover sediment cores from subglacial lakes and sedimentary basins in Antarctica's continental interior. While the existing inventory of cores has yielded important insights into the biotic and climatic evolution of Antarctica, strata have numerous and often lengthy time breaks, providing a framework of 'snapshots' through time. Further cores, and more work on existing cores, are needed to reconcile Antarctic records with the more continuous 'far-field' records documenting the evolution of global ice volume and deep-sea temperature. To achieve this, we argue for an integrated portfolio of drilling and coring missions that encompasses existing methodologies using ship- and sea-ice-/ice-shelf-based drilling platforms as well as recently developed seafloor-based drilling and subglacial access systems. We conclude by reviewing key technological issues that will need to be overcome.

Ice cover extent drives phytoplankton and bacterial community structure in a large north-temperate lake: implications for a warming climate.

Mid-winter limnological surveys of Lake Erie captured extremes in ice extent ranging from expansive ice cover in 2010 and 2011 to nearly ice-free waters in 2012. Consistent with a warming climate, ice cover on the Great Lakes is in decline, thus the ice-free condition encountered may foreshadow the lakes future winter state. Here, we show that pronounced changes in annual ice cover are accompanied by equally important shifts in phytoplankton and bacterial community structure. Expansive ice cover supported phytoplankton blooms of filamentous diatoms. By comparison, ice free conditions promoted the growth of smaller sized cells that attained lower total biomass. We propose that isothermal mixing and elevated turbidity in the absence of ice cover resulted in light limitation of the phytoplankton during winter. Additional insights into microbial community dynamics were gleaned from short 16S rRNA tag (Itag) Illumina sequencing. UniFrac analysis of Itag sequences showed clear separation of microbial communities related to presence or absence of ice cover. Whereas the ecological implications of the changing bacterial community are unclear at this time, it is likely that the observed shift from a phytoplankton community dominated by filamentous diatoms to smaller cells will have far reaching ecosystem effects including food web disruptions.

Prevalence and Types of Anemia and Associations with Functional Decline in Geriatric Inpatients.

BACKGROUND: The prevalence of anemia in hospitalized seniors has been linked to poor functional outcomes, increased mortality, and longer hospital stays, and has been associated with advancing age, male sex, and cognitive impairment. Despite the potential for complications, anemia often is undiagnosed and/or untreated in seniors. OBJECTIVES: Examine (a) the distribution of anemia diagnosis and treatment in patients in a rehabilitation hospital, and (b) patients' cognitive and functional outcomes. DESIGN: Retrospective chart review of medical records of 132 patients. MEASUREMENTS: The presence and type of anemia were determined based on the World Health Organization criteria for adults and Smith's algorithm, respectively. The Mini-Mental State Exam (MMSE) was used to measure cognitive status. Functional impairment was assessed using the Functional Independence Measure (FIM). RESULTS: The mean age of the sample was 82.20 years, with 68% being female, the mean MMSE and FIM scores were 23.95 (SD = 4.3) and 82.82 (SD = 15.63), respectively. In total, 67% of males and 46% of females were anemic (P < 0.05). The majority of anemias were caused by nutritional deficiencies. The percent of anemic females receiving treatment for anemia was higher (71%) than the percent of anemic males (46%) (P < 0.05). The majority of the patients improved functionally regardless of anemia status. CONCLUSIONS: Results indicated that a substantial number of patients in a geriatric hospital were anemic, with significant percentage going untreated. The overall improvement in patients' functional abilities suggests that remedial rehabilitation of frail seniors has an impact on recovery during their hospital stay.

Genetic and phenotypic parameters for carcass and meat quality traits in commercial crossbred pigs.

Pork quality and carcass characteristics are now being integrated into swine breeding objectives because of their economic value. Understanding the genetic basis for these traits is necessary for this to be accomplished. The objective of this study was to estimate phenotypic and genetic parameters for carcass and meat quality traits in 2 Canadian swine populations. Data from a genomic selection study aimed at improving meat quality with a mating system involving hybrid Landrace × Large White and Duroc pigs were used to estimate heritabilities and phenotypic and genetic correlations among them. Data on 2,100 commercial crossbred pigs for meat quality and carcass traits were recorded with pedigrees compromising 9,439 animals over 15 generations. Significant fixed effects (company, sex, and slaughter batch), covariates (cold carcass weight and slaughter age), and random additive and common litter effects were fitted in the models. A series of pairwise bivariate analyses were implemented in ASReml to estimate phenotypic and genetic parameters. Heritability estimates (±SE) for carcass traits were moderate to high and ranged from 0.22 ± 0.08 for longissimus dorsi muscle area to 0.63 ± 0.04 for trimmed ham weight, except for firmness, which was low. Heritability estimates (±SE) for meat quality traits varied from 0.10 ± 0.04 to 0.39 ± 0.06 for the Minolta b* of ham quadriceps femoris muscle and shear force, respectively. Generally, most of the genetic correlations were significant (P < 0.05) and ranged from low (0.18 ± 0.07) to high (-0.97 ± 0.35). There were high negative genetic correlations between drip loss with pH and shear force and a positive correlation with cooking loss. Genetic correlations between carcass weight (both hot and cold) with carcass marbling were highly positive. It was concluded that selection for increasing primal and subprimal cut weights with better pork quality may be possible. Furthermore, the use of pH is confirmed as an indicator for pork water-holding capacity and cooking loss. The heritabilities of carcass and pork quality traits indicated that they can be improved using traditional breeding methods and genomic selection, respectively. The estimated genetic parameters for carcass and meat quality traits can be incorporated into the breeding programs that emphasize product quality in these Canadian swine populations.

Diatom assemblages promote ice formation in large lakes.

We present evidence for the directed formation of ice by planktonic communities dominated by filamentous diatoms sampled from the ice-covered Laurentian Great Lakes. We hypothesize that ice formation promotes attachment of these non-motile phytoplankton to overlying ice, thereby maintaining a favorable position for the diatoms in the photic zone. However, it is unclear whether the diatoms themselves are responsible for ice nucleation. Scanning electron microscopy revealed associations of bacterial epiphytes with the dominant diatoms of the phytoplankton assemblage, and bacteria isolated from the phytoplankton showed elevated temperatures of crystallization (T(c)) as high as -3 °C. Ice nucleation-active bacteria were identified as belonging to the genus Pseudomonas, but we could not demonstrate that they were sufficiently abundant to incite the observed freezing. Regardless of the source of ice nucleation activity, the resulting production of frazil ice may provide a means for the diatoms to be recruited to the overlying lake ice, thereby increasing their fitness. Bacterial epiphytes are likewise expected to benefit from their association with the diatoms as recipients of organic carbon excreted by their hosts. This novel mechanism illuminates a previously undescribed stage of the life cycle of the meroplanktonic diatoms that bloom in Lake Erie and other Great Lakes during winter and offers a model relevant to aquatic ecosystems having seasonal ice cover around the world.

A failure of conflict to modulate dual-stream processing may underlie the formation and maintenance of delusions.

BACKGROUND: Dual-stream information processing proposes that reasoning is composed of two interacting processes: a fast, intuitive system (Stream 1) and a slower, more logical process (Stream 2). In non-patient controls, divergence of these streams may result in the experience of conflict, modulating decision-making towards Stream 2, and initiating a more thorough examination of the available evidence. In delusional schizophrenia patients, a failure of conflict to modulate decision-making towards Stream 2 may reduce the influence of contradictory evidence, resulting in a failure to correct erroneous beliefs. METHOD: Delusional schizophrenia patients and non-patient controls completed a deductive reasoning task requiring logical validity judgments of two-part conditional statements. Half of the statements were characterized by a conflict between logical validity (Stream 2) and content believability (Stream 1). RESULTS: Patients were significantly worse than controls in determining the logical validity of both conflict and non-conflict conditional statements. This between groups difference was significantly greater for the conflict condition. CONCLUSIONS: The results are consistent with the hypothesis that delusional schizophrenia patients fail to use conflict to modulate towards Stream 2 when the two streams of reasoning arrive at incompatible judgments. This finding provides encouraging preliminary support for the Dual-Stream Modulation Failure model of delusion formation and maintenance.

The casein kinase I family: roles in morphogenesis.

Wnt signals play important roles in development and oncogenesis and are transduced through at least two pathways: a canonical beta-catenin-dependent and a beta-catenin-independent cascade. Casein kinase I (CKI) is required in both invertebrates and vertebrates to transduce canonical Wnt signals. However, its role in the beta-catenin-independent pathway was unknown. During vertebrate embryogenesis, the beta-catenin-independent cascade is thought to control cell movements and has been postulated to be analogous to the Drosophila planar cell polarity pathway, which signals through the JNK cascade. Here, we report that blocking CKI function inhibits embryonic morphogenesis and activates JNK in cell lines. These studies suggest that CKI might also act in the beta-catenin-independent pathway and indicate a role for CKI during convergence extension in early vertebrate development.

The casein kinase I family in Wnt signaling.

The canonical Wnt-signaling pathway is critical for many aspects of development, and mutations in components of the Wnt pathway are carcinogenic. Recently, sufficiency tests identified casein kinase Iepsilon (CKIepsilon) as a positive component of the canonical Wnt/beta-catenin pathway, and necessity tests showed that CKIepsilon is required in vertebrates to transduce Wnt signals. In addition to CKIepsilon, the CKI family includes several other isoforms (alpha, beta, gamma, and delta) and their role in Wnt sufficiency tests had not yet been clarified. However, in Caenorhabditis elegans studies, loss-of-function of a CKI isoform most similar to alpha produced the mom phenotype, indicative of loss-of-Wnt signaling. In this report, we examine the ability of the various CKI isoforms to activate Wnt signaling and find that all the wild-type CKI isoforms do so. Dishevelled (Dsh), another positive component of the Wnt pathway, becomes phosphorylated in response to Wnt signals. All the CKI isoforms, with the exception of gamma, increase the phosphorylation of Dsh in vivo. In addition, CKI directly phosphorylates Dsh in vitro. Finally, we find that CKI is required in vivo for the Wnt-dependent phosphorylation of Dsh. These studies advance our understanding of the mechanism of Wnt action and suggest that more than one CKI isoform is capable of transducing Wnt signals in vivo.

A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization.

Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the 'iron hypothesis'. For this reason, it is important to understand the response of pelagic biota to increased iron supply. Here we report the results of a mesoscale iron fertilization experiment in the polar Southern Ocean, where the potential to sequester iron-elevated algal carbon is probably greatest. Increased iron supply led to elevated phytoplankton biomass and rates of photosynthesis in surface waters, causing a large drawdown of carbon dioxide and macronutrients, and elevated dimethyl sulphide levels after 13 days. This drawdown was mostly due to the proliferation of diatom stocks. But downward export of biogenic carbon was not increased. Moreover, satellite observations of this massive bloom 30 days later, suggest that a sufficient proportion of the added iron was retained in surface waters. Our findings demonstrate that iron supply controls phytoplankton growth and community composition during summer in these polar Southern Ocean waters, but the fate of algal carbon remains unknown and depends on the interplay between the processes controlling export, remineralisation and timescales of water mass subduction.

Casein kinase I transduces Wnt signals.

The Wnt signalling cascade is essential for the development of both invertebrates and vertebrates, and is altered during tumorigenesis. Although a general framework for Wnt signalling has been elucidated, not all of the components have been identified. Here we describe a serine kinase, casein kinase I (CKI), which was isolated by expression cloning in Xenopus embryos. CKI reproduces several properties of Wnt signals, including generation of complete dorsal axes, stabilization of beta-catenin and induction of genes that are direct targets of Wnt signals. Dominant-negative forms of CKI and a pharmacological blocker of CKI inhibited Wnt signals in Xenopus. Inhibiting CKI in Caenorhabditis elegans generated worms with a mom phenotype, indicative of a loss of Wnt signals. In addition, CKI bound to and increased the phosphorylation of dishevelled, a known component of the Wnt pathway. These data indicate that CKI may be a conserved component of the Wnt pathway.

Physiological and Biochemical Response of the Photosynthetic Apparatus of Two Marine Diatoms to Fe Stress.

Flavodoxin is a small electron-transfer protein capable of replacing ferredoxin during periods of Fe deficiency. When evaluating the suitability of flavodoxin as a diagnostic indicator for Fe limitation of phytoplankton growth, we examined its expression in two marine diatoms we cultured using trace-metal-buffered medium. Thalassio-sira weissflogii and Phaeodactylum tricornutum were cultured in ethylenediaminetetraacetic acid-buffered Sargasso Sea water containing from 10 to 1000 nM added Fe. Trace-metal-buffered cultures of each diatom maintained high growth rates across the entire range of Fe additions. Similarly, declines in chlorophyll/cell and in the ratio of photosystem II variable-to-maximum fluorescence were negligible (P. tricornutum) to moderate (T. weissflogii; 54% decline in chlorophyll/cell and 22% decrease in variable-to-maximum fluorescence). Moreover, only minor variations in photosynthetic parameters were observed across the range of additions. In contrast, flavodoxin was expressed to high levels in low-Fe cultures. Despite the inverse relationship between flavodoxin expression and Fe content of the medium, its expression was seemingly independent of any of the indicators of cell physiology that were assayed. It appears that flavodoxin is expressed as an early-stage response to Fe stress and that its accumulation need not be intimately connected to limitations imposed by Fe on the growth rate of these diatoms.

Preweaning growth of Yorkshire, Hampshire, and Landrace pigs.

Individual pig growth curves were derived on 445 Yorkshire, 323 Hampshire, and 316 Landrace boars and gilts. The range in age was from 1 to 35 d and these growth curves were linear. The regression parameters (x- and y-intercepts, and slopes) were different among the three breeds, and differences between boars and gilts were found in the Yorkshire breed for the y-intercept and slope and in the Landrace breed for the y-intercept and slope and in the Landrace breed for the y-intercept. An additional 130 Yorkshire, 126 Hampshire, and 96 Landrace boars and gilts were used to evaluate the effectiveness of adjustments that were additive, multiplicative, additive-multiplicative, or based on the x- and y-intercepts. Effectiveness was evaluated in terms of accuracy, equality of variance, and practical application. The multiplicative adjustments were the most effective in the Hampshire breed and the average of the additive and multiplicative adjustments was the most effective in the Yorkshire breed. In the Landrace breed none of the four methods evaluated produced a credible adjusted 21-d weight. From an industry standpoint this study suggests the need for breed-specific specific adjustments, and in some breeds this may have to be extended to sex-specific adjustments.

Phycoerythrin is absent from the pyrenoid of Porphyridium cruentum: photosynthetic implications.

The thylakoid lamellae which traverse the pyrenoid of the unicellular red alga Porphyridium cruentum (Agardh) Nägeli appear to lack phycobilisomes. We have confirmed by immuno-electron microscopy that phycoerythrin (PE), an important structural component of the phycobilisomes of red algae, is absent from the pyrenoid. To characterize pyrenoid thylakoids further, electron-microscopic cytochemical methods were employed to detect photosystem activity. Photosystem (PS) I activity was demonstrated in both stromal and pyrenoid thylakoids by the photooxidation of 3,3'-diaminobenzidine. In contrast, the localization of photoreduced distyryl nitroblue tetrazolium demonstrated that PSII activity was restricted to stromal thylakoids. The observed partitioning of PE and PSII activity within the plastid may be related to another observation, that being the localization of nearly all ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) within the pyrenoid of this alga. It is possible that the pyrenoid of P. cruentum functions as a specific metabolic compartment where CO2 fixation is enhanced by the absence of photosynthetic O2 evolution.

Vesiculo-bullous disorders in adulthood.

In this third and final article in the series on vesiculo-bullous disorders, I shall review some of the blistering diseases seen among adults. Many of the disorders are not common, but a delayed diagnosis can put the patient at risk. I shall mention some key aspects of the disease or its diagnosis, but for further detail, I refer the reader to the references cited.

Vesiculo-bullous disorders of the neonate.

This is the first of three articles which outline the diagnoses to be considered when vesiculo-bullous lesions are identified in the neonate, children, and adults. This paper presents a brief sketch of blistering disorders which may occur during the first few weeks of life. Vesiculo-bullous lesions in the neonate may represent benign, infectious, genetic, or life-threatening disorders. Early recognition, appropriate diagnostic procedures, and specific therapeutic interventions can be vital in reducing potential morbidity and mortality. General guidelines for diagnostic procedures and therapeutic interventions are discussed, along with some of the newer etiologic and epidemiologic concepts.

Vesiculo-bullous disorders in childhood.

This is the second of three articles outlining the diagnoses to be considered when vesiculo-bullous lesions are identified in the neonate, children, and adults. This paper deals with a number of blistering disorders which can arise throughout infancy and childhood. Both inherited and acquired diseases are considered, and general guidelines for diagnosis and management are discussed.

Prenatal and postnatal influences on growth and fat measurements in swine.

Data from 153 foster groups, each consisting of a dam and a nurse, were analyzed separately for breed (Lacombe, Yorkshire) parity (first, second), and sex of piglet (boar, gilt) to estimate prenatal, postnatal and prenatal X postnatal influences on growth and fat measurements. Significant differences were not observed between breeds, parity and sex of piglets; the estimates were pooled over these traits. Prenatal effects were the major contributing factor in the determination of preweaning growth rate, weaning weight, postweaning average daily gain and allometric growth coefficient, rib and loin fat deposition coefficients. Postnatal influence was of minor importance and the prenatal X postnatal interaction was of negligible consequence. These observations indicated that crossfostering of piglets between parities and breeds without regard for the sex of the piglet would not seriously bias subsequent performance testing results. Heritability estimates for weaning weight, postweaning growth rate and backfat thickness differed from published values.

Genetic correlation between boars, barrows and gilts for various carcass traits.

Data from 11 generations of a selection study were analyzed to estimate genetic correlations between boars and gilts, boars and barrows, and gilts and barrows for carcass traits in the Lacombe and Yorkshire breeds of swine. Genetic correlations were estimated to determine if genotype X sex interactions existed and to assess the need for separate genetic parameters for boars and gilts in selection response equations. Genotype X sex interactions were found for total carcass fat/kg of cold carcass weight, area of lean in the ham face/kg of cold carcass weight and percent lean in the ham face/kg of cold carcass weight. Carcass length, longissimus muscle area/kg of cold carcass weight percent ham of side and percent lean in the ham face did not have genotype X sex interactions. Selection based on pooled genetic parameters over sex were favored over selection based on separate genetic parameters regardless of the presence or absence of genotype X sex interactions.