bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of ocean acidification in naturally variable coral reef flat ecosystems
Authors: Shaw Emily C. , McNeil Ben I. , Tilbrook Bronte
Published: February 2012

Ocean acidification leads to changes in marine carbonate chemistry that are predicted to cause a decline in future coral reef calcification. Several laboratory and mesocosm experiments have described calcification responses of species and communities to increasing CO2. The few in situ studies on natural coral reefs that have been carried out to date have shown a direct relationship between aragonite saturation state (Ωarag) and net community calcification (Gnet). However, these studies have been performed over a limited range of Ωarag values, where extrapolation outside the observational range is required to predict future changes in coral reef calcification. We measured extreme diurnal variability in carbonate chemistry within a reef flat in the southern Great Barrier Reef, Australia. Ωarag varied between 1.1 and 6.5, thus exceeding the magnitude of change expected this century in open ocean subtropical/tropical waters. The observed variability comes about through biological activity on the reef, where changes to the carbonate chemistry are enhanced at low tide when reef flat waters are isolated from open ocean water. We define a relationship between net community calcification and Ωarag, using our in situ measurements. We find net community calcification to be linearly related to Ωarag, while temperature and nutrients had no significant effect on Gnet. Using our relationship between Gnet and Ωarag, we predict that net community calcification will decline by 55% of its preindustrial value by the end of the century. It is not known at this stage whether exposure to large variability in carbonate chemistry will make reef flat organisms more or less vulnerable to the non‐calcifying physiological effects of increasing ocean CO2 and future laboratory studies will need to incorporate this natural variability to address this question.
Hydraulic modeling of a distributary channel of Athabasca Valles, Mars, using a high‐resolution digital terrain model
Authors: McIntyre Neil , Warner Nicholas H. , Gupta Sanjeev , Kim Jung‐Rack , Muller Jan‐Peter
Published: February 2012

Estimating magnitudes of flow rates in outflow channels has a central role in developing understanding of the paleohydrology of Mars. The typical approach to flow estimation is to identify geomorphic features, which indicate bankfull levels, and then use a hydraulic model to convert these levels into flow rates. Data constraints have meant that important assumptions about model equations, boundary conditions and parameter values have been necessary. In this paper, we use a high‐resolution digital terrain model derived from NASA's Mars Reconnaissance Orbiter Context Camera stereopair imagery to develop a finer resolution step backwater hydraulic model than previously attempted. Furthermore, the data facilitate a more critical, more formal and broader assessment of this type of model than has previously been attempted. A distributary channel of Athabasca Valles is used as a case study. The median bankfull flow estimate was 39,000 m3 s−1, although estimates range up to 140,000 m3 s−1 depending on the assumptions employed. The principal uncertainties stem from assumptions about bankfull levels and downstream boundary conditions; and assumptions about the friction coefficient, criticality of flow, expansion and contraction losses, and geometric details of the channel are also important under certain conditions. Examination of additional DTMs further downstream would permit the analysis to be extended to hydraulic control sections that provide better‐known boundary conditions, hence improving flow estimates. It is concluded that new‐generation DTM data provide opportunity for deeper insight into the challenges and opportunities for modeling the paleohydrology of Mars, although further work is needed to achieve satisfactory levels of confidence.
Hydromechanical triggering of landslides: From progressive local failures to mass release
Authors: Lehmann Peter , Or Dani
Published: February 2012

Water infiltrating during intense rainfall on steep slopes gradually weakens the wet soil mass, inducing localized failures that may initiate a cascade of load redistributions and successive failures propagating across a hillslope. The challenge of linking the progressive nature of local events culminating in an abrupt landslide is addressed by a new hydromechanical triggering model that links key hydrologic processes with threshold‐based mechanical interactions. A hillslope is represented as assembly of soil columns interconnected by frictional and tensile mechanical bonds represented as virtual bundles of fibers. Increasing water load exerted on mechanical bonds causes gradual failure of fibers until restraining forces are exceeded. Following failure at the soil‐bedrock interface, the load on a column is redistributed to its neighbors via intact mechanical (primarily tensile) bonds which, in turn, may also fail and transmit the load downslope as compressive stresses. When soil internal compressive strength is exceeded, a load‐bearing column may liquefy and initiate a landslide release that could propagate downslope or retrogressively upslope. The model reproduces observed power law frequency magnitude relationships of landslides with exponents ranging between −1.0 and −2.2 in agreement with landslide inventory data. We applied a criticality measure defined by Ramos (2011) to evaluate the specific influences of slope angle, soil texture, and root reinforcement on attainment of hillslope criticality in which a small local failure may trigger release of a large soil mass. The model provides new insights on the conditions giving rise to an abrupt transition from a seemingly stable hillslope to a catastrophic landslide.
The earthquake magnitude is influenced by previous seismicity
Authors: Lippiello E. , Godano C. , de Arcangelis L.
Published: February 2012

Seismic occurrence is characterized by clustering in space, time and magnitude. Correlations between magnitudes of subsequent events have been recently attributed to catalog incompleteness. Here we investigate the effect of catalog completeness on the amplitude of magnitude correlations. The analysis of two California regions with different levels of catalog accuracy and different lower magnitude thresholds indicate that the amplitude of correlations does not depend on catalog incompleteness. Conversely, correlations are controlled by the probability that two events belong to the same mainshock‐aftershock sequence. Numerical simulations of the ETAS model, where magnitude correlations are absent by construction, provide a counter‐test supporting our conclusions.
The puzzle of DNA sequences of Phytoseiidae (Acari:Mesostigmata) in the public GenBank database
Authors: Tixier Marie-Stéphane , Hernandes Fabio Akashi , Guichou Sabine , Kreiter Serge
Published: February 2012

The public database GenBank is an increasingly important source of sequence data for diagnostic and phylogenetic research; however, not all deposited sequences are necessarily correctly ascribed to a source species. We considered the example of the mite family Phytoseiidae to determine how the corresponding sequences could be accurately exploited. Phytoseiidae mites are well known worldwide for their ability to control certain mite and insect pests. The number of molecular approaches, especially for diagnostic purposes, has increased over the past decade, leading to an increase in the number of sequences registered in the GenBank database. The aim of the present paper was to evaluate the validity of the DNA sequences presently assigned to Phytoseiidae species in this database. Three hundred and fifty-one sequences, corresponding to the four most frequently registered DNA fragments (ITS, COI, Cytb and 12S rRNA), were considered. DNA extraction, amplification and sequencing were performed for the fragments 12S rRNA and ITS for Amblyseius andersoni, A. swirskii, Iphiseius degenerans, Euseius ovalis, E. stipulatus, Neoseiulus cucumeris and Typhlodromus pyri, as some identifications were questionable. Numerous problems were evident based on genetic distance analyses of these sequences. First, nomenclatural problems were encountered, preventing the correct identification of the taxa sequenced in one case. Suspected misidentifications were frequent, stressing the importance of voucher specimen availability. For the 12S rRNA fragment, sequences assigned to three Phytoseiidae species were those of their prey (Astigmata), underlining the care that must be taken when manipulating the DNA of such predators (sterile conditions and specific PCR primers). Finally, sequences of two regions of the COI mtDNA were encountered, leading to alignment problems between sequences of a same gene and same species. These results are discussed in relation to responsibilities of authors in terms of taxon identification and the great utility of open access DNA sequence databases, such as GenBank, for improving taxonomic identifications and advancing scientific research.
Cortical reaction as an egg quality indicator in artificial reproduction of pikeperch, Sander lucioperca
Authors: Żarski Daniel , Krejszeff Sławomir , Palińska Katarzyna , Targońska Katarzyna , Kupren Krzysztof , Fontaine Pascal , Kestemont Patrick , Kucharczyk Dariusz
Published: February 2012

The aim of this study was to investigate the process of the cortical reaction in eggs of pikeperch, Sander lucioperca (L.), as well as the application of microscopic assessment of this process in egg quality evaluation. The analysis was carried out with eggs obtained from 10 females by artificial reproduction, in which hormonal stimulation with hCG was applied. Subsequently, each sample of eggs (separately from each female fish) was analysed. The analysis included observation of the cortical reaction and the process of egg swelling, and determination of the effect of temperature (12, 14 and 16°C) and the presence of spermatozoa on the cortical reaction. The results indicate that the cortical reaction in pikeperch eggs is quite violent, resulting in visible deformation of eggs between 3 and 5 min after activation. No effect of temperature or the presence of spermatozoa on the cortical reaction was observed. A strong correlation was recorded for the percentage of egg deformations observed and embryo survival rate. The described method of determination of pikeperch egg quality (based on egg deformation rate between 3 and 5 min after activation) may be highly useful, both in scientific research (where high-quality eggs are required) and in hatchery practice.
At 6–9 months, human infants know the meanings of many common nouns
Authors: Bergelson Elika , Swingley Daniel
Published: February 2012

It is widely accepted that infants begin learning their native language not by learning words, but by discovering features of the speech signal: consonants, vowels, and combinations of these sounds. Learning to understand words, as opposed to just perceiving their sounds, is said to come later, between 9 and 15 mo of age, when infants develop a capacity for interpreting others’ goals and intentions. Here, we demonstrate that this consensus about the developmental sequence of human language learning is flawed: in fact, infants already know the meanings of several common words from the age of 6 mo onward. We presented 6- to 9-mo-old infants with sets of pictures to view while their parent named a picture in each set. Over this entire age range, infants directed their gaze to the named pictures, indicating their understanding of spoken words. Because the words were not trained in the laboratory, the results show that even young infants learn ordinary words through daily experience with language. This surprising accomplishment indicates that, contrary to prevailing beliefs, either infants can already grasp the referential intentions of adults at 6 mo or infants can learn words before this ability emerges. The precocious discovery of word meanings suggests a perspective in which learning vocabulary and learning the sound structure of spoken language go hand in hand as language acquisition begins.
Structural basis for mutual relief of the Rac guanine nucleotide exchange factor DOCK2 and its partner ELMO1 from their autoinhibited forms
Authors: Hanawa-Suetsugu Kyoko , Kukimoto-Niino Mutsuko , Mishima-Tsumagari Chiemi , Akasaka Ryogo , Ohsawa Noboru , Sekine Shun-ichi , Ito Takuhiro , Tochio Naoya , Koshiba Seizo , Kigawa Takanori , Terada Takaho , Shirouzu Mikako , Nishikimi Akihiko , Uruno Takehito , Katakai Tomoya , Kinashi Tatsuo , Kohda Daisuke , Fukui Yoshinori , Yokoyama Shigeyuki
Published: February 2012

DOCK2, a hematopoietic cell-specific, atypical guanine nucleotide exchange factor, controls lymphocyte migration through ras-related C3 botulinum toxin substrate (Rac) activation. Dedicator of cytokinesis 2–engulfment and cell motility protein 1 (DOCK2•ELMO1) complex formation is required for DOCK2-mediated Rac signaling. In this study, we identified the N-terminal 177-residue fragment and the C-terminal 196-residue fragment of human DOCK2 and ELMO1, respectively, as the mutual binding regions, and solved the crystal structure of their complex at 2.1-Å resolution. The C-terminal Pro-rich tail of ELMO1 winds around the Src-homology 3 domain of DOCK2, and an intermolecular five-helix bundle is formed. Overall, the entire regions of both DOCK2 and ELMO1 assemble to create a rigid structure, which is required for the DOCK2•ELMO1 binding, as revealed by mutagenesis. Intriguingly, the DOCK2•ELMO1 interface hydrophobically buries a residue which, when mutated, reportedly relieves DOCK180 from autoinhibition. We demonstrated that the ELMO-interacting region and the DOCK-homology region 2 guanine nucleotide exchange factor domain of DOCK2 associate with each other for the autoinhibition, and that the assembly with ELMO1 weakens the interaction, relieving DOCK2 from the autoinhibition. The interactions between the N- and C-terminal regions of ELMO1 reportedly cause its autoinhibition, and binding with a DOCK protein relieves the autoinhibition for ras homolog gene family, member G binding and membrane localization. In fact, the DOCK2•ELMO1 interface also buries the ELMO1 residues required for the autoinhibition within the hydrophobic core of the helix bundle. Therefore, the present complex structure reveals the structural basis by which DOCK2 and ELMO1 mutually relieve their autoinhibition for the activation of Rac1 for lymphocyte chemotaxis.
Ancient climate change, antifreeze, and the evolutionary diversification of Antarctic fishes
Authors: Near Thomas J. , Dornburg Alex , Kuhn Kristen L. , Eastman Joseph T. , Pennington Jillian N. , Patarnello Tomaso , Zane Lorenzo , Fernández Daniel A. , Jones Christopher D.
Published: February 2012

The Southern Ocean around Antarctica is among the most rapidly warming regions on Earth, but has experienced episodic climate change during the past 40 million years. It remains unclear how ancient periods of climate change have shaped Antarctic biodiversity. The origin of antifreeze glycoproteins (AFGPs) in Antarctic notothenioid fishes has become a classic example of how the evolution of a key innovation in response to climate change can drive adaptive radiation. By using a time-calibrated molecular phylogeny of notothenioids and reconstructed paleoclimate, we demonstrate that the origin of AFGP occurred between 42 and 22 Ma, which includes a period of global cooling approximately 35 Ma. However, the most species-rich lineages diversified and evolved significant ecological differences at least 10 million years after the origin of AFGPs, during a second cooling event in the Late Miocene (11.6–5.3 Ma). This pattern indicates that AFGP was not the sole trigger of the notothenioid adaptive radiation. Instead, the bulk of the species richness and ecological diversity originated during the Late Miocene and into the Early Pliocene, a time coincident with the origin of polar conditions and increased ice activity in the Southern Ocean. Our results challenge the current understanding of the evolution of Antarctic notothenioids suggesting that the ecological opportunity that underlies this adaptive radiation is not linked to a single trait, but rather to a combination of freeze avoidance offered by AFGPs and subsequent exploitation of new habitats and open niches created by increased glacial and ice sheet activity.
Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum
Authors: Teicher Martin H. , Anderson Carl M. , Polcari Ann
Published: February 2012

Childhood maltreatment or abuse is a major risk factor for mood, anxiety, substance abuse, psychotic, and personality disorders, and it is associated with reduced adult hippocampal volume, particularly on the left side. Translational studies show that the key consequences of stress exposure on the hippocampus are suppression of neurogenesis in the dentate gyrus (DG) and dendritic remodeling in the cornu ammonis (CA), particularly the CA3 subfield. The hypothesis that maltreatment is associated with volume reductions in 3-T MRI subfields containing the DG and CA3 was assessed and made practical by newly released automatic segmentation routines for FreeSurfer. The sample consisted of 193 unmedicated right-handed subjects (38% male, 21.9 ± 2.1 y of age) selected from the community. Maltreatment was quantified using the Adverse Childhood Experience study and Childhood Trauma Questionnaire scores. The strongest associations between maltreatment and volume were observed in the left CA2-CA3 and CA4-DG subfields, and were not mediated by histories of major depression or posttraumatic stress disorder. Comparing subjects with high vs. low scores on the Childhood Trauma Questionnaire and Adverse Childhood Experience study showed an average volume reduction of 6.3% and 6.1% in the left CA2-CA3 and CA4-DG, respectively. Volume reductions in the CA1 and fimbria were 44% and 60% smaller than in the CA2-CA3. Interestingly, maltreatment was associated with 4.2% and 4.3% reductions in the left presubiculum and subiculum, respectively. These findings support the hypothesis that exposure to early stress in humans, as in other animals, affects hippocampal subfield development.
Arabidopsis
synchronizes jasmonate-mediated defense with insect circadian behavior
Authors: Goodspeed Danielle , Chehab E. Wassim , Min-Venditti Amelia , Braam Janet , Covington Michael F.
Published: February 2012

Diverse life forms have evolved internal clocks enabling them to monitor time and thereby anticipate the daily environmental changes caused by Earth's rotation. The plant circadian clock regulates expression of about one-third of the
Arabidopsis
genome, yet the physiological relevance of this regulation is not fully understood. Here we show that the circadian clock, acting with hormone signals, provides selective advantage to plants through anticipation of and enhanced defense against herbivory. We found that cabbage loopers (
Trichoplusia ni
) display rhythmic feeding behavior that is sustained under constant conditions, and plants entrained in light/dark cycles coincident with the entrainment of the
T. ni
suffer only moderate tissue loss due to herbivory. In contrast, plants entrained out-of-phase relative to the insects are significantly more susceptible to attack. The in-phase entrainment advantage is lost in plants with arrhythmic clocks or deficient in jasmonate hormone; thus, both the circadian clock and jasmonates are required. Circadian jasmonate accumulation occurs in a phase pattern consistent with preparation for the onset of peak circadian insect feeding behavior, providing evidence for the underlying mechanism of clock-enhanced herbivory resistance. Furthermore, we find that salicylate, a hormone involved in biotrophic defense that often acts antagonistically to jasmonates, accumulates in opposite phase to jasmonates. Our results demonstrate that the plant circadian clock provides a strong physiological advantage by performing a critical role in
Arabidopsis
defense.
Cellular solid-state nuclear magnetic resonance spectroscopy
Authors: Renault Marie , Tommassen-van Boxtel Ria , Bos Martine P. , Post Jan Andries , Tommassen Jan , Baldus Marc
Published: February 2012

Decrypting the structure, function, and molecular interactions of complex molecular machines in their cellular context and at atomic resolution is of prime importance for understanding fundamental physiological processes. Nuclear magnetic resonance is a well-established imaging method that can visualize cellular entities at the micrometer scale and can be used to obtain 3D atomic structures under in vitro conditions. Here, we introduce a solid-state NMR approach that provides atomic level insights into cell-associated molecular components. By combining dedicated protein production and labeling schemes with tailored solid-state NMR pulse methods, we obtained structural information of a recombinant integral membrane protein and the major endogenous molecular components in a bacterial environment. Our approach permits studying entire cellular compartments as well as cell-associated proteins at the same time and at atomic resolution.
Origin of first cells at terrestrial, anoxic geothermal fields
Authors: Mulkidjanian Armen Y. , Bychkov Andrew Yu. , Dibrova Daria V. , Galperin Michael Y. , Koonin Eugene V.
Published: February 2012

All cells contain much more potassium, phosphate, and transition metals than modern (or reconstructed primeval) oceans, lakes, or rivers. Cells maintain ion gradients by using sophisticated, energy-dependent membrane enzymes (membrane pumps) that are embedded in elaborate ion-tight membranes. The first cells could possess neither ion-tight membranes nor membrane pumps, so the concentrations of small inorganic molecules and ions within protocells and in their environment would equilibrate. Hence, the ion composition of modern cells might reflect the inorganic ion composition of the habitats of protocells. We attempted to reconstruct the “hatcheries” of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells. These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K
+
, Zn
2+
, Mn
2+
, and phosphate. Thus, protocells must have evolved in habitats with a high K
+
/Na
+
ratio and relatively high concentrations of Zn, Mn, and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under the anoxic, CO
2
-dominated primordial atmosphere, the chemistry of basins at geothermal fields would resemble the internal milieu of modern cells. The precellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapor that were lined with porous silicate minerals mixed with metal sulfides and enriched in K
+
, Zn
2+
, and phosphorous compounds.
N
-acetyl serotonin derivatives as potent neuroprotectants for retinas
Authors: Shen Jianying , Ghai Kanika , Sompol Pradoldej , Liu Xia , Cao Xuebing , Iuvone P. Michael , Ye Keqiang
Published: February 2012

N-acetylserotonin (NAS) is synthesized from serotonin by arylalkylamine
N
-acetyltransferase (AANAT), which is predominantly expressed in the pineal gland and retina. NAS activates TrkB in a circadian manner and exhibits antidepressant effects in a TrkB-dependent manner. It also enhances neurogenesis in hippocampus in sleep-deprived mice. Here we report the identification of NAS derivatives that possess much more robust neurotrophic effects with improved pharmacokinetic profiles. The compound
N
-[2-(5-
h
ydroxy-1H-
i
ndol-3-yl)ethyl]-2-
o
xopiperidine-3-
c
arboxamide (HIOC) selectively activates TrkB receptor with greater potency than NAS. It potently protects retinas from light-induced retinal degeneration (LIRD), which is tightly coupled with pronounced TrkB activation in retinas. Pharmacokinetic studies demonstrate that this compound is stable in serum and liver microsomes. It can pass the blood–brain barrier and blood–retinal barrier. Hence, HIOC is a good lead compound for further drug development for treating retinal degenerative diseases.
Discovery of a cytosolic/soluble ferroxidase in rodent enterocytes
Authors: Ranganathan Perungavur N. , Lu Yan , Fuqua Brie K. , Collins James F.
Published: February 2012

Hephaestin (Heph), a membrane-bound multicopper ferroxidase (FOX) expressed in duodenal enterocytes, is required for optimal iron absorption. However, sex-linked anemia (
sla
) mice harboring a 194-amino acid deletion in the Heph protein are able to absorb dietary iron despite reduced expression and mislocalization of the mutant protein. Thus Heph may not be essential, and mice are able to compensate for the loss of its activity. The current studies were undertaken to search for undiscovered FOXs in rodent enterocytes. An experimental approach was developed to investigate intestinal FOXs in which separate membrane and cytosolic fractions were prepared and FOX activity was measured by a spectrophotometric transferrin-coupled assay. Unexpectedly, FOX activity was noted in membrane and cytosolic fractions of rat enterocytes. Different experimental approaches demonstrated that cytosolic FOX activity was not caused by contamination with membrane Heph or a method-induced artifact. Cytosolic FOX activity was abolished by SDS and heat (78 °C), suggesting protein-mediated iron oxidation, and was also sensitive to Triton X-100. Furthermore, cytosolic FOX activity increased ∼30% in iron-deficient rats (compared with controls) but was unchanged in copper-deficient rats (in contrast to the reported dramatic reduction of Heph expression and activity during copper deficiency). Additional studies done in
sla
,
Heph
-knockout, and ceruloplasmin-knockout mice proved that cytosolic FOX activity could not be fully explained by Heph or ceruloplasmin. Therefore rodent enterocytes contain a previously undescribed soluble cytosolic FOX that may function in transepithelial iron transport and complement membrane-bound Heph.
Realistic simulation of the activation of voltage-gated ion channels
Authors: Dryga Anatoly , Chakrabarty Suman , Vicatos Spyridon , Warshel Arieh
Published: February 2012

Understanding the detailed mechanism of the activation of voltage-gated ion channels has been a problem of great current interest. Reliable molecular simulations of voltage effects present a major challenge because meaningful converging microscopic simulations are not yet available and macroscopic treatments involve major uncertainties regarding the dielectric constant used and other key features. The current work has overcome some of the above challenges by using our recently developed coarse-grained (CG) model in simulating the activation of the Kv1.2 channel. The CG model has allowed us to explore problems that cannot be addressed at present by fully microscopic simulations, while providing insights on some features that are not usually considered in continuum models, including the distribution of the electrolytes between the membrane and the electrodes during the activation process and thus the nature of the gating current. Furthermore, the clear connection to microscopic descriptions combined with the power of CG modeling offers a powerful tool for exploring the energy balance between the protein conformational energy and the interaction with the external potential in voltage-activated channels. Our simulations have reproduced the observed experimental trend of the gating charge and, most significantly, the correct trend in the free energies, where the closed channel is more stable at negative potential and the open channel is more stable at positive potential. Moreover, we provide a unique view of the activation landscape and the time dependence of the activation process.
Spontaneous generation of rapidly transmissible prions in transgenic mice expressing wild-type bank vole prion protein
Authors: Watts Joel C. , Giles Kurt , Stöhr Jan , Oehler Abby , Bhardwaj Sumita , Grillo Sunny K. , Patel Smita , DeArmond Stephen J. , Prusiner Stanley B.
Published: February 2012

Currently, there are no animal models of the most common human prion disorder, sporadic Creutzfeldt-Jakob disease (CJD), in which prions are formed spontaneously from wild-type (WT) prion protein (PrP). Interestingly, bank voles (BV) exhibit an unprecedented promiscuity for diverse prion isolates, arguing that bank vole PrP (BVPrP) may be inherently prone to adopting misfolded conformations. Therefore, we constructed transgenic (Tg) mice expressing WT BVPrP. Tg(BVPrP) mice developed spontaneous CNS dysfunction between 108 and 340 d of age and recapitulated the hallmarks of prion disease, including spongiform degeneration, pronounced astrogliosis, and deposition of alternatively folded PrP in the brain. Brain homogenates of ill Tg(BVPrP) mice transmitted disease to Tg(BVPrP) mice in ∼35 d, to Tg mice overexpressing mouse PrP in under 100 d, and to WT mice in ∼185 d. Our studies demonstrate experimentally that WT PrP can spontaneously form infectious prions in vivo. Thus, Tg(BVPrP) mice may be useful for studying the spontaneous formation of prions, and thus may provide insight into the etiology of sporadic CJD.
Critical quasiparticle theory applied to heavy fermion metals near an antiferromagnetic quantum phase transition
Authors: Abrahams Elihu , Wölfle Peter
Published: February 2012

We use the recently developed critical quasiparticle theory to derive the scaling behavior associated with a quantum critical point in a correlated metal. This is applied to the magnetic-field induced quantum critical point observed in YbRh
2
Si
2
, for which we also derive the critical behavior of the specific heat, resistivity, thermopower, magnetization and susceptibility, the Grüneisen coefficient, and the thermal expansion coefficient. The theory accounts very well for the available experimental results.
Glucocorticoids interact with the hippocampal endocannabinoid system in impairing retrieval of contextual fear memory
Authors: Atsak Piray , Hauer Daniela , Campolongo Patrizia , Schelling Gustav , McGaugh James L. , Roozendaal Benno
Published: February 2012

There is extensive evidence that glucocorticoid hormones impair the retrieval of memory of emotionally arousing experiences. Although it is known that glucocorticoid effects on memory retrieval impairment depend on rapid interactions with arousal-induced noradrenergic activity, the exact mechanism underlying this presumably nongenomically mediated glucocorticoid action remains to be elucidated. Here, we show that the hippocampal endocannabinoid system, a rapidly activated retrograde messenger system, is involved in mediating glucocorticoid effects on retrieval of contextual fear memory. Systemic administration of corticosterone (0.3–3 mg/kg) to male Sprague–Dawley rats 1 h before retention testing impaired the retrieval of contextual fear memory without impairing the retrieval of auditory fear memory or directly affecting the expression of freezing behavior. Importantly, a blockade of hippocampal CB1 receptors with AM251 prevented the impairing effect of corticosterone on retrieval of contextual fear memory, whereas the same impairing dose of corticosterone increased hippocampal levels of the endocannabinoid 2-arachidonoylglycerol. We also found that antagonism of hippocampal β-adrenoceptor activity with local infusions of propranolol blocked the memory retrieval impairment induced by the CB receptor agonist WIN55,212–2. Thus, these findings strongly suggest that the endocannabinoid system plays an intermediary role in regulating rapid glucocorticoid effects on noradrenergic activity in impairing memory retrieval of emotionally arousing experiences.
Portrayal of females in magazine advertisements in Hong Kong
Authors: Chan Kara , Cheng Yolanda
Published: February 2012

A content analysis was conducted to examine the portrayal of beauty types and occupational roles of female figures in magazine advertisements. A systematic random sample of 215 advertisements from a popular lifestyle magazine in Hong Kong was analyzed. Results provide evidence of gender role stereotypes. Two thirds of the advertisements adopted classic/feminine beauty type. The other two common beauty types were sex kitten and casual. Over-representation of Caucasian models was found as one-third of the female figures were Caucasian and other minorities. Caucasian models were more likely to be portrayed in trendy beauty type. Over half of the advertisements portrayed females in decorative roles and thirty percent portrayed females as celebrities. Recreational roles and professional roles were featured less frequently. Advertisements for products target females were more gender stereotyped than advertisements for products target males and females. The lack of variety in beauty types and occupational roles among female figures were discussed.
Impolite orders in Ancient Greek?
Authors: Denizot Camille
Published: February 2012

In Ancient Greek, an impolite order can be uttered by means of a negative interrogative in the future tense (οὐκ ἐρεῖς; ‘Won’t you talk?’). The aim of this paper is to understand to what extent this type of utterance is impolite, and to explain how such a conventional and indirect order can frequently take on an impolite meaning. For this purpose, data are taken from classical drama (Aristophanes’ and Euripides’ plays).

Drawing on criteria put forward by recent work on impoliteness, this study provides an accurate description of uses in discourse, in order to establish that this conventional order is never used with a polite intention, but regularly as an impolite order. Impoliteness can be explained by the locutionary form which gives an orientation to the interpretation of the utterance: an indirect and conventional expression cannot be polite if the locutionary meaning is opposed to it.
Bathythermal Habitat Use by Strains of Great Lakes‐ and Finger Lakes‐Origin Lake Trout in Lake Huron after a Change in Prey Fish Abundance and Composition
Authors: Bergstedt Roger A. , Argyle Ray L. , Krueger Charles C. , Taylor William W.
Published: February 2012

A study conducted in Lake Huron during October 1998–June 2001 found that strains of Great Lakes‐origin (GLO) lake trout Salvelinus namaycush occupied significantly higher temperatures than did Finger Lakes‐origin (FLO; New York) lake trout based on data from archival (or data storage) telemetry tags that recorded only temperature. During 2002 and 2003, we implanted archival tags that recorded depth as well as temperature in GLO and FLO lake trout in Lake Huron. Data subsequently recorded by those tags spanned 2002–2005. Based on those data, we examined whether temperatures and depths occupied by GLO and FLO lake trout differed during 2002–2005. Temperatures occupied during those years were also compared with occupied temperatures reported for 1998–2001, before a substantial decline in prey fish biomass. Temperatures occupied by GLO lake trout were again significantly higher than those occupied by FLO lake trout. This result supports the conclusion of the previous study. The GLO lake trout also occupied significantly shallower depths than FLO lake trout. In 2002–2005, both GLO and FLO lake trout occupied significantly lower temperatures than they did in 1998–2001. Aside from the sharp decline in prey fish biomass between study periods, the formerly abundant pelagic alewife Alosa pseudoharengus virtually disappeared and the demersal round goby Neogobius melanostomus invaded the lake and became locally abundant. The lower temperatures occupied by lake trout in Lake Huron during 2002–2005 may be attributable to changes in the composition of the prey fish community, food scarcity (i.e., a retreat to cooler water could increase conversion efficiency), or both.
Processing of representations in declarative and procedural working memory
Authors: Souza Alessandrada Silva , Oberauer Klaus , Gade Miriam , Druey Michel D.
Published: February 2012

The article investigates the relation between declarative and procedural working memory (WM; Oberauer, 2009). Two experiments test the assumption that representations in the two subsystems are selected for processing in analogous ways. Participants carried out a series of decisions on memorized lists of digits. For each decision, they had to select declarative and procedural representations. Regarding declarative representations, participants selected a memory set and a digit within this set as the input to each decision. With respect to the procedural representations, they selected a task set to be applied to the selected digit and a response within that task set. We independently manipulated the number of lists and the number of tasks to be switched among (one, two, or three; Experiment 1) and preparation time for a list switch (Experiment 2). For three effects commonly observed in task-switch studies, analogues in declarative WM were found: list-switch costs, mixing costs, and residual switch costs. List- and task-switch costs were underadditive, suggesting that declarative and procedural representations are selected separately and in parallel. The findings support the hypothesis of two analogous WM subsystems.
Structure–function mapping of a heptameric module in the nuclear pore complex
Authors: Fernandez-Martinez Javier , Phillips Jeremy , Sekedat Matthew D. , Diaz-Avalos Ruben , Velazquez-Muriel Javier , Franke Josef D. , Williams Rosemary , Stokes David L. , Chait Brian T. , Sali Andrej , Rout Michael P.
Published: February 2012

The nuclear pore complex (NPC) is a multiprotein assembly that serves as the sole mediator of nucleocytoplasmic exchange in eukaryotic cells. In this paper, we use an integrative approach to determine the structure of an essential component of the yeast NPC, the ∼600-kD heptameric Nup84 complex, to a precision of ∼1.5 nm. The configuration of the subunit structures was determined by satisfaction of spatial restraints derived from a diverse set of negative-stain electron microscopy and protein domain–mapping data. Phenotypic data were mapped onto the complex, allowing us to identify regions that stabilize the NPC’s interaction with the nuclear envelope membrane and connect the complex to the rest of the NPC. Our data allow us to suggest how the Nup84 complex is assembled into the NPC and propose a scenario for the evolution of the Nup84 complex through a series of gene duplication and loss events. This work demonstrates that integrative approaches based on low-resolution data of sufficient quality can generate functionally informative structures at intermediate resolution.
Thymic negative selection is functional in NOD mice
Authors: Mingueneau Michael , Jiang Wenyu , Feuerer Markus , Mathis Diane , Benoist Christophe
Published: February 2012

Based on analyses of multiple TCR transgenic (tg) models, the emergence of pathogenic T cells in diabetes-prone NOD mice has been ascribed to a failure to censure autoreactive clones in the thymus. In contrast, using isolated and preselected thymocytes, we show that nonobese diabetic (NOD) genetic variation impairs neither clonal deletion nor downstream transcriptional programs. However, we find that NOD genetic variation influences αβ/γδ-lineage decisions promoted by early expression of tg αβ-TCRs at the double-negative (DN) stage. In B6 and other genetic backgrounds, tg αβ-TCRs behave like γδ-TCRs and commit a large fraction of DNs toward the γδ-lineage, thereby decreasing the size of the double-positive (DP) pool, which is efficiently positively and negatively selected. In NOD DNs, αβ-TCR signalosomes instead behave like pre-TCRs, resulting in high numbers of DPs competing for limited selection niches, and poor positive and negative selection. Once niche effects are neutralized in mixed bone marrow chimeras, positive and negative selection are equally efficient on B6 and NOD backgrounds. Biochemical analysis revealed a selective defect in the activation of Erk1/2 downstream of NOD αβ-TCR signalosomes. Therefore, NOD genetic variation influences αβ/γδ-lineage decisions when the αβ-TCR heterodimer is prematurely expressed, but not the process of negative selection.
On The Electrotonic Spread in Cardiac Muscle of the Mouse
Authors: TANAKA ICHIRO , SASAKI YUTAKA
Published: February 2012

As an appropriate model which can simulate the cardiac working muscle with respect to the passive electrical spread, a lattice whose sides have linear cable properties is presented, and the passive potential spread on the model is mathematically analyzed in the fiber direction. Distribution of electrotonic potential in the fiber direction was measured with a pair of intracellular microelectrodes in the cardiac muscle fiber of mouse. By employing “pencil type” microelectrodes potential distribution in the transverse direction within a fiber was also measured. This transverse effect was differentiated from the longitudinal potential distribution. A tonically applied potential at any point of a cell interior spreads continuously in a manner described by a Bessel function. Using appropriate electrical and morphological parameters the experimental results proved to fit the curve obtained from numerical calculation on the model. The apparent length constant obtained for smaller distances (less than 100 μ) from the current source was 70 μ, and it increases as the distance becomes larger. At a point inside the fiber the resistance to the extracellular fluid ranged from 200 to 600 KΩ. The influence of coupling resistance between current and recording electrodes on the measurement of electrotonic potential was examined for small interelectrode distance.
Spectral measures and Cuntz algebras
Authors: Dutkay Dorin , Jorgensen Palle
Published: February 2012

We consider a family of measures

μ
\mu

supported in

R

d

\mathbb {R}^d

and generated in the sense of Hutchinson by a finite family of affine transformations. It is known that interesting sub-families of these measures allow for an orthogonal basis in

L
2

(
μ
)

L^2(\mu )

consisting of complex exponentials, i.e., a Fourier basis corresponding to a discrete subset

Γ
\Gamma

in

R

d

\mathbb {R}^d

. Here we offer two computational devices for understanding the interplay between the possibilities for such sets

Γ
\Gamma

(spectrum) and the measures

μ
\mu

themselves. Our computations combine the following three tools: duality, discrete harmonic analysis, and dynamical systems based on representations of the Cuntz

C
∗

C^*

-algebras

O

N

\mathcal O_N

.
Species identification in seamount fish aggregations using moored underwater video
Authors: O'Driscoll Richard L. , de Joux Peter , Nelson Richard , Macaulay Gavin J. , Dunford Adam J. , Marriott Peter M. , Stewart Craig , Miller Brian S.
Published: February 2012

O'Driscoll, R. L., de Joux, P., Nelson, R., Macaulay, G. J., Dunford, A. J., Marriott, P. M., Stewart, C., and Miller, B. S. 2012. Species identification in seamount fish aggregations using moored underwater video. – ICES Journal of Marine Science, 69: 648–659. Acoustic surveys of New Zealand deep-water seamounts often show fish aggregations up to 150 m high on the summit. Although bottom trawls on the seamount slopes catch predominantly orange roughy (Hoplostethus atlanticus), species composition in the midwater plumes is extremely uncertain. In June 2010, moored underwater video cameras were deployed on the summit of the Morgue seamount (summit depth 890 m), a feature that has been closed to fishing since 2001. Cameras and lights were timed to come on for 2 min every 2 h. Fish response to the mooring was monitored using vessel-mounted echosounders. Moored cameras confirmed that orange roughy were present up to 70 m above the seamount summit. Orange roughy made up 97% of the fish identified from the video. Other species observed included smooth oreo (Pseudocyttus maculatus), spiky oreo (Neocyttus rhomboidalis), deep-water dogfish, cardinalfish (Epigonus spp.), and squid. Total along-track backscatter from the plume varied by a factor of 25 over a period of hours. Peak acoustic densities in the plume (equivalent to 20 orange roughy m−3) were an order of magnitude higher than peak visual estimates (0.64 orange roughy m−3), but relative densities between paired video and acoustic observations were generally consistent.
Implications of using alternative methods of vessel monitoring system (VMS) data analysis to describe fishing activities and impacts
Authors: Lambert Gwladys I. , Jennings Simon , Hiddink Jan Geert , Hintzen Niels T. , Hinz Hilmar , Kaiser Michel J. , Murray Lee G.
Published: February 2012

Lambert, G. I., Hiddink, J. G., Hintzen, N. T., Hinz, H., Kaiser, M. J., Murray, L. G., and Jennings, S. 2012. Implications of using alternative methods of vessel monitoring system (VMS) data analysis to describe fishing activities and impacts. – ICES Journal of Marine Science, 69: 682–693. Understanding the spatial distribution and intensity of fishing activity is a prerequisite for estimating fishing impacts on seabed biota and habitats. Vessel monitoring system data provide information on fishing activity at large spatial scales. However, successive position records can be too infrequent to describe the complex movements fishing vessels make. High-frequency position data were collected to evaluate how polling frequency and the method of analysis influenced the estimates of fishing impact on the seabed and associated epifaunal communities. Comparisons of known positions with predictions from track interpolation revealed that the performance of interpolation depended on fleet behaviour. Descriptions and indicators of fishing intensity were influenced significantly by the analytical methods (track reconstruction, density of position records) and grid-cell resolution used for the analysis. These factors can lead to an underestimation of fishing impact on epifaunal communities. It is necessary to correct for such errors to quantify the effects of fishing on various ecosystem components and hence to inform ecosystem-based management. Polling at intervals of 30 min would provide a desirable compromise between achieving precise estimates of fishing impacts on the seabed and minimizing the cost of data collection and handling.
Implementation Science and Practice
Authors: Proctor Enola K. , Powell Byron , McGinnis Hollee
Published: February 2012

Evidence-based practice (EBP) has been increasingly advocated and is gaining wider acceptance in social work. This signals a continuing reaffirmation of social work’s commitment to generating and maintaining a scientific knowledge base in general and, more specifically, to an expectation that social work be informed by, and based on, evidence from scientific research. Yet actual implementation of evidence-based programs, services, and practices remains a formidable challenge. In most areas of health and human services, evidence-based care comprises only a small fraction of all the care that is actually delivered. We have little if any data on the proportion of actual social work services that are evidence based. In response to the challenge of moving evidence-based practice from the research environment to real-world care, a growing literature addresses the science and practice of translation, and specifically the implementation of evidence-based practices. Translational science is a broad field that pertains to the progression from basic biological research to its application for public health benefit. Implementation research is a subset of translational research, although some literatures use these terms interchangeably. Literature on implementation reflects an early stage of science, for we have much to learn about the factors that enhance implementation, and even more to learn about actual strategies implementing evidence-based practices and the methodology for studying implementation processes. The literature discussed in this entry is drawn from a range of disciplines, because social work journals have published very few articles about implementation and because implementation itself is an inherently transdisciplinary topic.