bluuebunny/crossref_metadata_2025 huggingface dataset:
Northward movement of Martian dust localized in the region of the Hellas Basin
Authors: Ogohara Kazunori , Satomura Takehiko
Published: July 2008

Transportation of dust in and around the Hellas Basin is simulated using a Martian atmospheric general circulation model. Results of numerical experiments show that dust, originally localized near the southwestern rim of the Hellas Basin, moves northward by the southerly wind along the west inner rim of the Hellas Basin. The southerly wind is on average approximately 5 m s−1 and is significantly stronger at nighttime. It is indicated that the time‐averaged southerly wind is associated with a steady barotropic structure of meridional wind in and above the Hellas Basin. It is also suggested that baroclinic waves and downslope wind on the southern slope of the Hellas Basin enhance the southerly wind. The relevance of the movement of local dust storms near the Hellas Basin to the early phase of the global dust storm in 2001 is also discussed.
Posteruptive phenomena in coronal mass ejections and substorms: Indicators of a universal process?
Authors: Reeves K. K. , Guild T. B. , Hughes W. J. , Korreck K. E. , Lin J. , Raymond J. , Savage S. , Schwadron N. A. , Spence H. E. , Webb D. F. , Wiltberger M.
Published: July 2008

We examine phenomena associated with eruptions in the two different regimes of the solar corona and the terrestrial magnetosphere. We find striking similarities between the speeds of shrinking magnetic field lines in the corona and dipolarization fronts traversing the magnetosphere. We also examine the similarities between supra‐arcade downflows observed during solar flares and bursty bulk flows seen in the magnetotail and find that these phenomena have remarkably similar speeds, velocity profiles, and size scales. Thus we show manifest similarities in the magnetic reconfiguration in response to the ejection of coronal mass ejections in the corona and the ejection of plasmoids in the magnetotail. The subsequent return of loops to a quasi‐potential state in the corona and field dipolarization in the magnetotail are physical analogs and trigger similar phenomena such as downflows, which provides key insights into the underlying drivers of the plasma dynamics.
Circulating Endothelial Progenitor Cells as a Pathogenetic Marker of Moyamoya Disease
Authors: Jung Keun-Hwa , Chu Kon , Lee Soon-Tae , Park Hee-Kwon , Kim Dong-Hyun , Kim Jin-Hee , Bahn Jae-Jun , Song Eun-Cheol , Kim Manho , Lee Sang Kun , Roh Jae-Kyu
Published: July 2008

Moyamoya disease (MMD) is an unusual form of chronic cerebrovascular occlusive disease that involves the formation of characteristically abnormal vessels. Recent studies have reported that colony-forming unit (CFU) and outgrowth cells represent a subpopulation of endothelial progenitor cells (EPCs). Here, we attempted to determine the significance of CFU number and outgrowth cell yield in MMD. Endothelial progenitor cells were isolated from the blood of 24 adult MMD patients and from 48 age- and risk factor-matched control subjects. After 7 days of culture, CFUs were determined, and yields of outgrowth cells were measured during 2 months of culture. The EPC function was also evaluated using matrigel plate assays. It was found that CFU numbers were significantly lower in MMD patients than in controls. Moreover, during long-term culture, outgrowth cells were isolated from only 10% of control subjects but from 33% of MMD patients, and CFU numbers and tube formation were found to be lower in advanced MMD cases than in those with early stage disease, whereas outgrowth cells were more frequently detected in those with early MMD and moyamoya vessels than in those with advanced disease. These characteristics of circulating EPCs reflect mixed conditions of vascular occlusion and abnormal vasculogenesis during the pathogenesis of MMD.
Metabolic Challenge to Glia Activates an Adenosine-Mediated Safety Mechanism that Promotes Neuronal Survival by Delaying the Onset of Spreading Depression Waves
Authors: Canals Santiago , Larrosa Belén , Pintor Jesús , Mena María A , Herreras Oscar
Published: July 2008

In a model of glial-specific chemical anoxia, we have examined how astrocytes influence both synaptic transmission and the viability of hippocampal pyramidal neurons. This relationship was assessed using electrophysiological, pharmacological, and biochemical techniques in rat slices and cell cultures, and oxidative metabolism was selectively impaired in glial cells by exposure to the mitochondrial gliotoxin, fluoroacetate. We found that synaptic transmission was blocked shortly after inducing glial metabolic stress and peri-infarct-like spreading depression (SD) waves developed within 1 to 2 h of treatment. Neuronal electrogenesis was not affected until SD waves developed, thereafter decaying irreversibly. The blockage of synaptic transmission was totally reversed by A1 adenosine receptor antagonists, unlike the development of SD waves, which appeared earlier under these conditions. Such blockage led to a marked reduction in the electrical viability of pyramidal neurons 1 h after gliotoxin treatment. Cell culture experiments confirmed that astrocytes indeed release adenosine. We interpret this early glial response as a novel safety mechanism that allocates metabolic resources to vital processes when the glia itself sense an energy shortage, thereby delaying or preventing entry into massive lethal ischemic-like depolarization. The implication of these results on the functional recovery of the penumbra regions after ischemic insults is discussed.
Transcriptomic Screening of Microvascular Endothelial Cells Implicates Novel Molecular Regulators of Vascular Dysfunction after Spinal Cord Injury
Authors: Benton Richard L , Maddie Melissa A , Worth Christopher A , Mahoney Edward T , Hagg Theo , Whitternore Scott R
Published: July 2008

Microvascular dysfunction is a critical pathology that underlies the evolution of secondary injury mechanisms after traumatic spinal cord injury (SCI). However, little is known of the molecular regulation of endothelial cell (EC) plasticity observed acutely after injury. One reason for this is the relative lack of methods to quickly and efficiently obtain highly enriched spinal microvascular ECs for high-throughput molecular and biochemical analyses. Adult C57BI/6 mice received an intravenous injection of fluorescein isothiocyanate (FITC)-conjugated Lycopersicon esculentum lectin, and FITC-lectin bound spinal microvessels were greatly enriched by fluorescence-activated cell sorter (FACS) purification. This technique allows for rapid (< 1.5 h postmortem) isolation of spinal cord microvascular ECs (smvECs). The results from cell counting, reverse-transcription polymerase chain reaction (RT-PCR), and western blot analyses show a high degree of EC enrichment at mRNA and protein levels. Furthermore, a focused EC biology microarray analysis identified multiple mRNAs dramatically increased in the EC compartment 24 h after SCI, which is a time point associated with the pathologic loss of spinal vasculature. These included thrombospondin-1, CCL5/RANTES, and urokinase plasminogen activator, suggesting they may represent targets for therapeutic intervention. Furthermore, these novel methodologic approaches will likely facilitate the discovery of molecular regulators of endothelial dysfunction in a variety of central nervous system (CNS) disorders including stroke and other neurodegenerative diseases having a vascular component.
Actions of a nitric oxide donor on prostaglandin production and angiogenic activity in the equine endometrium
Authors: Roberto da Costa Rosário P. , Costa Ana S. , Korzekwa Anna J. , Platek Rafal , Siemieniuch Marta , Galvão António , Redmer Dale A. , Silva José Robalo , Skarzynski Dariusz J. , Ferreira-Dias Graça
Published: July 2008

Nitric oxide (NO) plays an important role in prostaglandin secretion and angiogenesis in the reproductive system. In the present study, the roles of the NO donor spermine NONOate and tumour necrosis factor-α (TNF; as a positive control) in prostaglandin production and angiogenic activity of equine endometria during the oestrous cycle were evaluated. In addition, the correlation between NO production and the expression of key prostaglandin synthase proteins was determined. The protein expression of prostaglandin F synthase (PGFS) increased in early and mid-luteal stages, whereas that of prostaglandin E synthase (PGES) was increased in the early luteal stage. The in vitro release of NO was highest after ovulation. There was a high correlation between NO production and PGES expression, as well as NO release and PGFS expression. There were no differences detected in prostaglandin H synthase 2 (PTGS-2) throughout the oestrous cycle and there was no correlation between PTGS-2 expression and NO. In TNF- or spermine-treated endometria, the expression of prostaglandin (PG) E2 increased in the early and mid-luteal phases, whereas that of PGF2α increased in the follicular and late luteal phases. Bovine aortic endothelial cell (BAEC) proliferation was stimulated in TNF-treated follicular-phase endometria. However, in spermine-treated endometria, NO delivered from its donor had no effect, or even an inhibitory effect, on BAEC proliferation. In conclusion, despite no change in PTGS-2 expression throughout the oestrous cycle in equine endometrial tissue, there were changes observed in the expression of PGES and PGFS, as well as in the production of PGE2 and PGF2α. In the mare, NO is involved in the secretory function of the endometrium, modulating PGE2 and PGF2α production. Even though TNF caused an increase in the production of angiogenic factors and prostaglandins, its complex action in mare uterus should be elucidated.
Cyclic-AMP initiates protein tyrosine phosphorylation independent of cholesterol efflux during ram sperm capacitation
Authors: Colas Carmen , James Peter , Howes Liz , Jones Roy , Cebrian-Perez José A. , Muiño-Blanco Teresa
Published: July 2008

Unlike most other species, ram spermatozoa are difficult to capacitate in vitro. Bicarbonate and Ca2+ are necessary, whereas bovine serum albumin does not appear to be obligatory. In the present investigation we have assessed (1) the ability of the cholesterol-sequestering agent, methyl-β-cyclodextrin (M-β-CD), to initiate protein tyrosine phosphorylation, and (2) the importance of phosphodiesterases (PDEs) in controlling the levels of cAMP. Results show that despite removing significant amounts of membrane cholesterol, as assessed by filipin staining, M-β-CD treatment did not stimulate major increases in protein tyrosine phosphorylation. Addition of a cocktail of PDE inhibitors (theophylline and caffeine), a phosphatase inhibitor (okadaic acid) and dibutyryl-cAMP (db-cAMP), however, stimulated specific tyrosine phosphorylation of several proteins between 30 and 120 kDa. On their own, none of the above reagents were effective but a combination of db-cAMP + PDE inhibitors was sufficient to achieve a maximal response. H-89, a protein kinase-A inhibitor, suppressed tyrosine phosphorylation significantly. Immunofluorescence revealed that the newly-phosphorylated proteins localised mainly in the sperm tail. These findings suggest that in ram spermatozoa cAMP levels are too low to initiate tyrosine phosphorylation of flagellar proteins that are indicative of the capacitation state and that this is caused by unusually high levels of intracellular PDEs.
Effect of duration of oocyte maturation on the kinetics of cleavage, embryo yield and sex ratio in cattle
Authors: Rizos Dimitrios , Bermejo-Alvarez Pablo , Gutierrez-Adan Alfonso , Lonergan Patrick
Published: July 2008

The aim of the present study was to examine the effect of maturation for 16 v. 24 h on the kinetics of development and the sex ratio of bovine embryos. Oocytes were inseminated at 16 or 24 h after the beginning of maturation using frozen–thawed bull semen. Two-cell embryos at 24, 28, 32, 36, 40, 44 and 48 h post-insemination (hpi) and blastocysts at Days 6, 7 and 8 from both groups were snap-frozen individually and stored at –80°C until determination of embryo sex. Insemination at 16 h resulted in a lower cleavage rate at 48 hpi than insemination at 24 h (70.6% v. 77.1%, respectively, P < 0.05). In terms of the evolution of cleavage divisions, insemination at 24 h resulted in a typical pattern of cleavage such that by 32 hpi, ~58% of presumptive zygotes had cleaved. In contrast, first cleavage following insemination at 16 h was significantly slower such that by 32 hpi, ~35% of presumptive zygotes had cleaved. Duration of IVM did not affect blastocyst yield (~37%). The overall sex ratio of 2-cell embryos at 48 hpi differed from 1 : 1 in favour of males in both groups (24 h: 55.9 v. 44.1%; 16 h: 59.1 v. 40.9%, P < 0.05). Similarly, the overall sex ratio of blastocysts differed from 1 : 1 in both groups (24 h: 59.7 v. 40.3%; 16 h: 58.5 v. 41.5%, P < 0.05). In conclusion, timing of gamete interaction and maturity of the oocyte at the time of the interaction can affect the kinetics of the early cleavage divisions but has no effect on the sex ratio of the embryos produce.
A remark on global positioning from local distances
Authors: Singer Amit
Published: July 2008

Finding the global positioning of points in Euclidean space from a local or partial set of pairwise distances is a problem in geometry that emerges naturally in sensor networks and NMR spectroscopy of proteins. We observe that the eigenvectors of a certain sparse matrix exactly match the sought coordinates. This translates to a simple and efficient algorithm that is robust to noisy distance data.
Bioinformatic method for protein thermal stabilization by structural entropy optimization
Authors: Bae Euiyoung , Bannen Ryan M. , Phillips George N.
Published: July 2008

Engineering proteins for higher thermal stability is an important and difficult challenge. We describe a bioinformatic method incorporating sequence alignments to redesign proteins to be more stable through optimization of local structural entropy. Using this method, improved configurational entropy (ICE), we were able to design more stable variants of a mesophilic adenylate kinase with only the sequence information of one psychrophilic homologue. The redesigned proteins display considerable increases in their thermal stabilities while still retaining catalytic activity. ICE does not require a three-dimensional structure or a large number of homologous sequences, indicating a broad applicability of this method. Our results also highlight the importance of entropy in the stability of protein structures.
Electrostatic funneling of substrate in mitochondrial inner membrane carriers
Authors: Wang Yi , Tajkhorshid Emad
Published: July 2008

Exchange of ATP and ADP across mitochondrial membrane replenishes the cytoplasm with newly synthesized ATP and provides the mitochondria with the substrate ADP for oxidative phosphorylation. The sole means of this exchange is the mitochondrial ADP/ATP carrier (AAC), a membrane protein that is suggested to cycle between two conformationally distinct states, cytosolic-open (c-state) and matrix-open (m-state), thereby shuttling nucleotides across the inner mitochondrial membrane. However, the c-state is the only structurally resolved state, and the binding site of ADP remains elusive. Here, we present ≈0.3 μs of all-atom MD simulations of the c-state revealing rapid, spontaneous binding of ADP to deeply positioned binding sites within the AAC lumen. To our knowledge, a complete ligand-binding event has heretofore not been described in full atomic detail in unbiased simulations. The identified ADP-bound state and additional simulations shed light on key structural elements and the initial steps involved in conversion to the m-state. Electrostatic analysis of trajectories reveals the presence of an unusually strong positive electrostatic potential in the lumen of AAC that appears to be the main driving force for the observed spontaneous binding of ADP. We provide evidence that the positive electrostatic potential is likely a common attribute among the entire family of mitochondrial carriers. In addition to playing a key role in substrate recruitment and translocation, the electropositivity of mitochondrial carriers might also be critical for their binding to the negatively charged environment of the inner mitochondrial membrane.
Solution structure of the U2 snRNP protein Rds3p reveals a knotted zinc-finger motif
Authors: van Roon Anne-Marie M. , Loening Nikolaus M. , Obayashi Eiji , Yang Ji-Chun , Newman Andrew J. , Hernández Helena , Nagai Kiyoshi , Neuhaus David
Published: July 2008

Rds3p, a component of the U2 snRNP subcomplex SF3b, is essential for pre-mRNA splicing and is extremely well conserved in all eukaryotic species. We report here the solution structure of Rds3p, which reveals an unusual knotted fold unrelated to previously known knotted proteins. Rds3p has a triangular shape with a GATA-like zinc finger at each vertex. Pairs of cysteines contributing to each finger are arranged nonsequentially in a permuted arrangement reminiscent of domain-swapping but which here involves segments of subdomains within a single chain. We suggest that the structure arose through a process of segment swapping after gene duplication. The fingers are connected through β-strands and loops, forming an overall topology strongly resembling a “triquetra knot.” The conservation and surface properties of Rds3p suggest that it functions as a platform for protein assembly within the multiprotein SF3b complex of U2 snRNP. The recombinant protein used for structure determination is biologically active, as it restores splicing activity in a yeast splicing extract depleted of native Rds3p.
Earlier Violent Television Exposure and Later Drug Dependence
Authors: Brook David W. , Saar Naomi S. , Brook Judith S.
Published: July 2008

This research examined the longitudinal pathways from earlier violent television exposure to later drug dependence. African American and Puerto Rican adolescents were interviewed during three points in time (n = 463). Exposure to violent television programs in late adolescence predicted exposure to violent television programs in young adulthood, which in turn was related to tobacco/marijuana use, nicotine dependence, and later drug dependence. Some policy and clinical implications suggest regulating the times when violent television programs are broadcast, creating developmentally targeted prevention/treatment programs, and recognizing that watching violent television programs may serve as a cue regarding increased susceptibility to nicotine and drug dependence.
Contingent Reinforcement of Personal Goal Activities for Adolescents with Substance Use Disorders During Post‐Residential Continuing Care
Authors: Godley Susan H. , Godley Mark D. , Wright Kelli L. , Funk Rodney R. , Petry Nancy M.
Published: July 2008

Contingency management (CM) is efficacious in improving outcomes of substance‐abusing patients, but CM studies are relatively rare in adolescents. CM approaches can reinforce both abstinence and adherence to treatment‐related goal areas. This paper describes 1,739 different activities in 10 goal areas (e.g., education, family/friends, and social/recreational) chosen by 86 adolescents who were participating in a multiple week CM study that reinforced both abstinence and adherence with goal‐related activities. The mean activities selected was 20, and the mean completed was 13. Overall, 1,114 or 64% of chosen activities were completed. The clinical feasibility of activity incentive programs for adolescents is discussed.
Effectiveness of Community‐Based Treatment for Problem Gambling: A Quasi‐Experimental Evaluation of Cognitive‐Behavioral vs. Twelve‐Step Therapy
Authors: Toneatto Tony , Dragonetti Rosa
Published: July 2008

With the increasing availability of gambling throughout North America, there is interest in developing more effective treatments. This study compares the effectiveness of two brief outpatient treatments for problem gambling: eight sessions of Cognitive‐Behavioral Therapy (n = 65) and eight sessions of a twelve‐step treatment‐oriented approach based on the first five steps of Gamblers Anonymous (n = 61). There were no baseline group differences on gambling‐relevant variables. Twelve months post‐treatment showed no group differences on key gambling variables (eg, frequency, abstinence rates, money wagered) in an analysis of completers. Participants who attended more sessions and chose an initial abstinent treatment goal appeared to achieve better outcomes.
Infrequent Illicit Methadone Use Among Stimulant‐Using Patients in Methadone Maintenance Treatment Programs: A National Drug Abuse Treatment Clinical Trials Network Study
Authors: Wu Li‐Tzy , Blazer Dan G. , Stitzer Maxine L. , Patkar Ashwin A. , Blaine Jack D.
Published: July 2008

We sought to determine the prevalence, patterns, and correlates of past‐month illicit methadone use and history of regular illicit use among stimulant‐using methadone maintenance treatment patients. We obtained self‐reported information on illicit methadone use from 383 participants recruited from six community‐based methadone maintenance programs. Overall, 1.6% of participants reported illicit use in the past month, and 4.7% reported a history of regular use. Younger age and history of outpatient psychological treatment were associated with increased odds of past‐month illicit use. Illicit methadone use among patients in maintenance programs is infrequent; however, a number of factors may increase risk of illicit use.
Systematic Assessment of Gamma Hydroxybutyrate (GHB) Effects During and After Acute Intoxication
Authors: Kim Susan Y. , Barker Judith C. , Anderson Ilene B. , Dyer Jo Ellen , Earnest Gillian , Blanc Paul D.
Published: July 2008

We adapted and tested a previously published questionnaire battery eliciting sensory and cognitive symptoms during (acute) and immediately after (post‐acute) GHB intoxication. Studying 125 GHB users, we assessed the instrument's internal consistency using Cronbach's alpha (CA) and responsiveness to change comparing acute and post‐acute symptoms. The final 14‐item battery demonstrated good internal consistency (CA ≥ 0.85, both acute and post‐acute). The median symptom score (possible range 0–64) was 30 (acute) and 6 (post‐acute; difference p < 0.001). This modified substance‐specific symptom battery, which is easily administered, demonstrated excellent performance characteristics. It can be used to study GHB and, potentially, related drugs of abuse.
Sex Differences in the Heritability of Alcohol Problems
Authors: Hardie Thomas L. , Moss Howard B. , Lynch Kevin Gerard
Published: July 2008

Genetic factors may have a role in defining more coherent clinical phenotypes and subtypes in the DSM‐V. Research has demonstrated that there are gender differences in the patterns of alcohol consumption, specific symptom endorsement, withdrawal effects, and rates of alcohol use disorders (AUD). We examined the sex‐specific heritability of diagnostic symptoms for alcohol‐related problems in a community‐based sample of twin pairs (males: n = 519; females: n = 613) using a biometrical analytic strategy to estimate the genetic and environmental components of AUD symptoms. Five of the seven symptoms of alcohol problems demonstrated sex‐differences in heritability. Three of the seven symptoms examined had significant heritability in female twins only: “increased risk of injury or harm,” “emotional problems related to drinking,” and “the desire to drink.” In males, a different pattern was observed, with four of the seven examined symptoms demonstrating heritability: “Increased chance of injury or harm,” “spending more time using alcohol or getting over its effects,” “using larger amounts for longer periods of time than intended,” and “the need to use more alcohol to get the same effect.” These data suggest that alcohol problems in females and males may be etiologically distinct, and that diagnostic criteria and therapeutics might be enhanced if these sex differences were taken into consideration.
Being an academic: authorship, authenticity and authority
Authors: Ruth Damian
Published: July 2008

The author's experience of three common academic activities – the production of a portfolio, the preparation of a CV and the submission of a research assessment report – are related respectively to authorship, authenticity and authority. A comparison is made of how the 'being
of' an academic is expressed in these three textual enactments of academic life. The author analyses how his experience illustrates 'the terrors of performativity' (Ball 2003) and he concludes that this illuminates how personal violation parallels our barbarous treatment of the environment
and many of the peoples in it; as our education becomes more systematised, more managed, more 'effective' in economic terms, it offers less and less of a barrier to social barbarity.
Dead academics: what can we learn about academic work and life from obituaries?
Authors: Tight Malcolm
Published: July 2008

This article analyses the obituaries of 100 academics published in the British quality press in 2007 to see what they tell us about the changing nature of contemporary academic work, and how it is presented in this particular genre of writing. It concludes that the influence of Oxbridge
and the American higher education system, and the dominance of men, remain strong in the senior levels of academic life that make it into the obituary pages. The obituaries also illustrate the impact of global events and trends, such as world war and the international mobility of highly skilled
labour, on academe. At an individual level, they present a picture of almost mythic achievement, brought down to earth by accounts of caring and essential eccentricity.
Discovering regulatory motifs in the Plasmodium genome using comparative genomics
Authors: Wu Jie , Sieglaff Douglas H. , Gervin Joshua , Xie Xiaohui S.
Published: July 2008

Motivation: Understanding gene regulation in Plasmodium, the causative agent of malaria, is an important step in deciphering its complex life cycle as well as leading to possible new targets for therapeutic applications. Very little is known about gene regulation in Plasmodium, and in particular, few regulatory elements have been identified. Such discovery has been significantly hampered by the high A-T content of some of the genomes of Plasmodium species, as well as the challenge in associating discovered regulatory elements to gene regulatory cascades due to Plasmodium's complex life cycle.

Results: We report a new method of using comparative genomics to systematically discover motifs in Plasmodium without requiring any functional data. Different from previous methods, our method does not depend on sequence alignments, and thus is particularly suitable for highly divergent genomes. We applied our method to discovering regulatory motifs between the human parasite, P.falciparum, and its rodent-infectious relative, P.yoelii. We also tested our procedure against comparisons between P.falciparum and the primate-infectious, P.knowlesi. Our computational effort leads to an initial catalog of 38 distinct motifs, corresponding to over 16 200 sites in the Plasmodium genome. The functionality of these motifs was further supported by their defined distribution within the genome as well as a correlation with gene expression patterns. This initial map provides a systematic view of gene regulation in Plasmodium, which can be refined as additional genomes become available.

Availability: The new algorithm, named motif discovery using orthologous sequences (MDOS), is available at http://www.ics.uci.edu/∼xhx/project/mdos/.

Contact:  xhx@ics.uci.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Ecology and evolution join forces to good effect
Authors: Barrett Rowan D.H , Vamosi Jana C
Published: July 2008

The 3rd regular meeting of the Canadian Society of Ecology and Evolution was held at the University of British Columbia, Vancouver, Canada from 11 to 14 May 2008.
Mathematical models of energy homeostasis
Authors: Pattaranit Ratchada , van den Berg Hugo Antonius
Published: July 2008

Diabetes and obesity present a mounting global challenge. Clinicians are increasingly turning to mechanism-based mathematical models for a quantitative definition of physiological defects such as insulin resistance, glucose intolerance and elevated obesity set points, and for predictions of the likely outcomes of therapeutic interventions. However, a very large range of such models is available, making a judicious choice difficult. To better inform this choice, here we present the most important models published to date in a uniform format, discussing similarities and differences in terms of the decisions faced by modellers. We review models for glucostasis, based on the glucose–insulin feedback control loop, and consider extensions to long-term energy balance, dislipidaemia and obesity.
Mammalian choices: combining fast-but-inaccurate and slow-but-accurate decision-making systems
Authors: Trimmer Pete C , Houston Alasdair I , Marshall James A.R , Bogacz Rafal , Paul Elizabeth S , Mendl Mike T , McNamara John M
Published: July 2008

Empirical findings suggest that the mammalian brain has two decision-making systems that act at different speeds. We represent the faster system using standard signal detection theory. We represent the slower (but more accurate) cortical system as the integration of sensory evidence over time until a certain level of confidence is reached. We then consider how two such systems should be combined optimally for a range of information linkage mechanisms. We conclude with some performance predictions that will hold if our representation is realistic.
Life history constrains biochemical development in the highly specialized odontocete echolocation system
Authors: Koopman Heather N , Zahorodny Zoey P
Published: July 2008

The vertebrate head has undergone enormous modification from the features borne by early ancestors. The growth of skull bones has been well studied in many species, yet little is known about corresponding soft tissue development. Among mammals, some of the most unusual examples of cranial evolution exist in the toothed whales (odontocetes). Specialized fat bodies in toothed whale heads play important roles in sound transmission and reception. These fat bodies contain unique endogenous lipids, with favourable acoustic properties, arranged in highly organized, three-dimensional patterns. We link variation in developmental rates of acoustic fats with life-history strategy, using bottlenose dolphins and harbour porpoises. Porpoise acoustic fats attain adult configurations earlier (less than 1 year) and at a faster pace than dolphins. The accelerated lipid accumulation in porpoises reflects the earlier need for fully functional echolocation systems. Dolphins enjoy 3–6 years of maternal care; porpoises must achieve total independence by approximately nine months. Further, a stereotypic ‘blueprint’ for the spatial distribution of lipids is established prior to birth, demonstrating the highly conserved nature of the intricate biochemical arrangement in acoustic tissues. This system illustrates an unusual case of soft tissue development being constrained by life history, rather than the more commonly observed mechanistic or phyletic constraints.
An ancient tripartite symbiosis of plants, ants and scale insects
Authors: Ueda Shouhei , Quek Swee-Peck , Itioka Takao , Inamori Keita , Sato Yumiko , Murase Kaori , Itino Takao
Published: July 2008

In the Asian tropics, a conspicuous radiation ofMacarangaplants is inhabited by obligately associatedCrematogasterants tendingCoccus(Coccidae) scale insects, forming a tripartite symbiosis. Recent phylogenetic studies have shown that the plants and the ants have been codiversifying over the past 16–20 million years (Myr). The prevalence of coccoids in ant–plant mutualisms suggest that they play an important role in the evolution of ant–plant symbioses. To determine whether the scale insects were involved in the evolutionary origin of the mutualism betweenMacarangaandCrematogaster, we constructed a cytochrome oxidase I (COI) gene phylogeny of the scale insects collected from myrmecophyticMacarangaand estimated their time of origin based on a COI molecular clock. The minimum age of the associatedCoccuswas estimated to be half that of the ants, at 7–9 Myr, suggesting that they were latecomers in the evolutionary history of the symbiosis.Crematogastermitochondrial DNA (mtDNA) lineages did not exhibit specificity towardsCoccusmtDNA lineages, and the latter was not found to be specific towardsMacarangataxa, suggesting that patterns of associations in the scale insects are dictated by opportunity rather than by specialized adaptations to host plant traits.
Glucocorticoids enhance taste aversion memory via actions in the insular cortex and basolateral amygdala
Authors: Miranda Maria Isabel , Quirarte Gina L. , Rodriguez-Garcia Gabriela , McGaugh James L. , Roozendaal Benno
Published: July 2008

It is well established that glucocorticoid hormones strengthen the consolidation of hippocampus-dependent spatial and contextual memory. The present experiments investigated glucocorticoid effects on the long-term formation of conditioned taste aversion (CTA), an associative learning task that does not depend critically on hippocampal function. Corticosterone (1.0 or 3.0 mg/kg) administered subcutaneously to male Sprague–Dawley rats immediately after the pairing of saccharin consumption with the visceral malaise-inducing agent lithium chloride (LiCl) dose-dependently increased aversion to the saccharin taste on a 96-h retention test trial. In a second experiment, rats received corticosterone either immediately after saccharin consumption or after the LiCl injection, when both stimuli were separated by a 3-h time interval, to investigate whether corticosterone enhances memory of the gustatory or visceral stimulus presentation. Consistent with the finding that the LiCl injection, but not saccharin consumption, increases endogenous corticosterone levels, corticosterone selectively enhanced CTA memory when administered after the LiCl injection. Suppression of this training-induced release of corticosterone with the synthesis-inhibitor metyrapone (35 mg/kg) impaired CTA memory, and was dose-dependently reversed by post-training supplementation of corticosterone. Moreover, direct post-training infusions of corticosterone into the insular cortex or basolateral complex of the amygdala, two brain regions that are critically involved in the acquisition and consolidation of CTA, also enhanced CTA retention, whereas post-training infusions into the dorsal hippocampus were ineffective. These findings provide evidence that glucocorticoid effects on memory consolidation are not limited to hippocampus-dependent spatial/contextual information, but that these hormones also modulate memory consolidation of discrete-cue associative learning via actions in other brain regions.
Sphingolipid Long-Chain Base Hydroxylation Is Important for Growth and Regulation of Sphingolipid Content and Composition inArabidopsis
Authors: Chen Ming , Markham Jennifer E. , Dietrich Charles R. , Jaworski Jan G. , Cahoon Edgar B.
Published: July 2008

Sphingolipids are structural components of endomembranes and function through their metabolites as bioactive regulators of cellular processes such as programmed cell death. A characteristic feature of plant sphingolipids is their high content of trihydroxy long-chain bases (LCBs) that are produced by the LCB C-4 hydroxylase. To determine the functional significance of trihydroxy LCBs in plants, T-DNA double mutants and RNA interference suppression lines were generated for the two Arabidopsis thaliana LCB C-4 hydroxylase genes Sphingoid Base Hydroxylase1 (SBH1) and SBH2. These plants displayed reductions in growth that were dependent on the content of trihydroxy LCBs in sphingolipids. Double sbh1 sbh2 mutants, which completely lacked trihydroxy LCBs, were severely dwarfed, did not progress from vegetative to reproductive growth, and had enhanced expression of programmed cell death associated–genes. Furthermore, the total content of sphingolipids on a dry weight basis increased as the relative amounts of trihydroxy LCBs decreased. In trihydroxy LCB–null mutants, sphingolipid content was ∼2.5-fold higher than that in wild-type plants. Increases in sphingolipid content resulted from the accumulation of molecular species with C16 fatty acids rather than with very-long-chain fatty acids, which are more commonly enriched in plant sphingolipids, and were accompanied by decreases in amounts of C16-containing species of chloroplast lipids. Overall, these results indicate that trihydroxy LCB synthesis plays a central role in maintaining growth and mediating the total content and fatty acid composition of sphingolipids in plants.
Incommensurate structure of InAl1 − x
Ti
x
O3 + x/2 [x = 0.701 (1)]: comparison between modulated and composite models
Authors: Bereciartua P. J. , Zuñiga F. J. , Breczewski T.
Published: July 2008

The structure of the monoclinic phase of the compound InAl1 − x
Ti
x
O3 + x/2 with x = 0.701 (1) has been analyzed within the (3 + 1)-dimensional superspace formalism. Two different models were refined describing the structure as an incommensurate modulated layer and modulated composite, respectively. Both models include the same composition–structure relation. In the composite approach it is derived from the mismatching between the two subsystems. In the incommensurate modulated system, it is derived from a closeness condition between O atomic domains. The distribution and coordination of the cations is discussed and compared with previously proposed models for similar compounds.
On the correlations between the polyhedron eccentricity parameters and the bond-valence sums for the cations with one lone electron pair
Authors: Sidey Vasyl
Published: July 2008

Applicability of the Wang–Liebau polyhedron eccentricity parameter in the bond-valence model [Wang & Liebau (2007). Acta Cryst. B63, 216–228] has been found to be doubtful: the correlations between the values of the polyhedron eccentricity parameters and the bond-valence sums calculated for the cations with one lone electron pair are probably an artifact of the poorly determined bond-valence parameters.
Interaction geometries and energies of hydrogen bonds to C=O and C=S acceptors: a comparative study
Authors: Wood Peter A. , Pidcock Elna , Allen Frank H.
Published: July 2008

The occurrence, geometries and energies of hydrogen bonds from N—H and O—H donors to the S acceptors of thiourea derivatives, thioamides and thiones are compared with data for their O analogues – ureas, amides and ketones. Geometrical data derived from the Cambridge Structural Database indicate that hydrogen bonds to the C=S acceptors are much weaker than those to their C=O counterparts: van der Waals normalized hydrogen bonds to O are shorter than those to S by ∼ 0.25 Å. Further, the directionality of the approach of the hydrogen bond with respect to S, defined by the C=S...H angle, is in the range 102–109°, much lower than the analogous C=O...H angle which lies in the range 127–140°. Ab initio calculations using intermolecular perturbation theory show good agreement with the experimental results: the differences in hydrogen-bond directionality are closely reproduced, and the interaction energies of hydrogen bonds to S are consistently weaker than those to O, by ∼ 12 kJ mol−1, for each of the three compound classes. There are no CSD examples of hydrogen bonds to aliphatic thiones, (Csp
3)2C=S, consistent with the near-equality of the electronegativities of C and S. Thioureas and thioamides have electron-rich N substituents replacing the Csp
3 atoms. Electron delocalization involving C=S and the N lone pairs then induces a significant >Cδ+=Sδ− dipole, which enables the formation of the medium-strength C=S...H bonds observed in thioureas and thioamides.
Incommensurate structure of Ca2Al2O5 at high temperatures – structure investigation and Raman spectroscopy
Authors: Lazic Biljana , Krüger Hannes , Kahlenberg Volker , Konzett Jürgen , Kaindl Reinhard
Published: July 2008

A high-temperature X-ray diffraction study revealed that brownmillerite-type Ca2Al2O5 transforms to an incommensurately modulated structure at elevated temperatures. Single crystals of Ca2Al2O5 were synthesized in an end-loaded piston cylinder press at 2.5 GPa and 1273 K. The diffraction pattern observed at 1090 (10) K by in situ single-crystal diffraction experiments can be indexed by an I-centred orthorhombic cell and a modulation wavevector of q = 0.595 (1)c
*. A (3 + 1)-dimensional model in superspace group Imma(00γ)s00 was used to refine the modulated structure. The structure is assembled from two building units: (i) layers of corner-sharing [AlO6] octahedra, stacked along b alternate with (ii) layers of zweier single chains of [AlO4] tetrahedra running along a. The modulated structure arises from an aperiodic sequence of two different configurations of the chains within the tetrahedral layers. The modulated high-temperature phase of Ca2Al2O5 is isotypic to the modulated high-temperature modification of Ca2Fe2O5. A large hysteresis was found in the phase-transition temperature. On heating, the transition occurs at ca 1075 (10) K; on cooling, satellite reflections can be observed down to 975 (10) K. The characterization of Ca2Al2O5 is completed by Raman spectroscopy, including a partial interpretation of the spectra.
Effects of site fidelity and breeding performance on mate retention in a short‐lived passerine, the tree swallowThachycineta bicolor
Authors: Llambías Paulo E. , Wrege Peter , Winkler David W.
Published: July 2008

We studied the relationship among re‐mating, site fidelity and breeding performance in the tree swallowTachycineta bicolorusing 16 y of data on reproductive biology in a population breeding in nest boxes near Ithaca, New York. Of 217 pairs for which both members survived the non‐breeding season, 76% mated with a new partner and 24% reunited with their previous mate. Pairs did not increase their breeding success by breeding together for more than one breeding season. Males produced fewer fledglings after breeding with a new partner, but females neither increased nor decreased their success when breeding with a new mate. Females who bred with a new partner were younger than females that reunited with their previous mates, and they were more likely to move to a different nest box. Males that bred with a new mate were of similar age to males that reunited, and they did not move more often. The probability of breeding with a new partner was better predicted by female age than by previous breeding success, suggesting that re‐mating was not strongly affected by past breeding performance. Because younger females change breeding sites more frequently than do older females and females that mated with a new partner were younger than females that reunited with their previous mates, we suggest that the tendency of tree swallows to change partners between years is a by‐product of lower site fidelity of younger females rather than a strategy for increasing breeding success.
Effects of blood collection on wild birds: an update
Authors: Sheldon Lani D. , Chin Eunice H. , Gill Sharon A. , Schmaltz Gregory , Newman Amy E. M. , Soma Kiran K.
Published: July 2008

Blood sampling is often critical for answering a variety of questions about wild birds. However, it is important to assess the impacts, if any, of blood collection on wild birds. Here, we examined the effects of blood sampling on adults or nestlings in three species of free‐living birds. First, we examined the effects of blood collection on annual survival and reproductive success in adult buff‐breasted wrens Thryothorus leucotis in Panama. In adult wrens, blood collection from the brachial vein during the breeding season had no effect on annual survival or reproductive success. Second, we examined whether blood collection influenced mass gain in developing smooth‐billed anis Crotophaga ani in Puerto Rico. In developing anis, blood collection from the femoral or jugular veins had no effect on mass gain of nestlings. Third, in developing European starlings Sturnus vulgaris in British Columbia, Canada, blood collection from the brachial vein had no effect of body condition. Blood collection from the jugular vein had a transient effect on body condition during the first week post‐hatch, but this effect disappeared by the second week of age. Lastly, we present an extensive up‐to‐date review of the literature on the effects of blood collection on free‐living avian species. Taken together, these data show that blood collection has no major negative effects on developing or adult birds in the wild.
The role of pheromones in freshwater fishes
Authors: Burnard D. , Gozlan R. E. , Griffiths S. W.
Published: July 2008

The study of fish pheromones is particularly relevant because of the conserved nature of chemoreception in vertebrates. However, most fish pheromone systems remain unstudied. All the major known pheromones of freshwater fish and their associated behaviours were reviewed. Importantly, those studies that have demonstrated the connection between behaviour and pheromones in freshwater fishes have resulted in a wide range of applications in management. For example, pheromones released by the sea lampreyPetromyzon marinushave a practical function in pheromone traps, showing how chemical communication can be used in the management of invasive species. Future research on fish pheromones should include olfactory systems in a wider range of species testing the possibility that a few distinct models could be applied to the all fishes. Progress in research on fish pheromones should include a closer collaboration with other research fields such as evolutionary biology to allow a better understanding of fish pheromones systems divergence and mate selection where correlation between phenotypic dominance and pheromone production is still largely ignored. Finally, the example of pheromone interaction between an invasive species topmouth gudgeonPseudorasbora parvaand a native endangered species sunbleakLeucaspius delineatusis provided to illustrate the concept of pheromone pollution that assists its establishment in a novel ecosystem.
Wild Atlantic salmon Salmo salar L. strains have greater growth potential than a domesticated strain selected for fast growth
Authors: Neregård L. , Sundt‐Hansen L. , Hindar K. , Einum S. , Johnsson J. I. , Devlin R. H. , Fleming I. A. , Björnsson B. Th.
Published: July 2008

A study was undertaken to examine the responses of three Atlantic salmon Salmo salar strains to growth hormone (GH) treatment. A positive growth response to sustained‐release GH implants was found in two wild strains (Namsen and Imsa) as well as one domesticated strain (AquaGen). The data revealed that the growth‐selected AquaGen strain has further growth potential, however, a stronger growth response was observed in the wild strains which outgrew the domesticated strain after GH treatment. These observations suggest that some growth potential may have been lost during the selection for rapid growth in the AquaGen strain. In September, the parr were GH implanted and in December sampled for plasma GH and insulin‐like growth factor I (IGF‐I) levels, liver, muscle and gill GH receptor, IGF‐I mRNA levels, gill Na+,K+‐ATPase activity, muscle and liver lipid content and body silvering. Low temperature and seasonal growth cessation probably explains the relatively limited GH effects found. Body silvering in all strains was positively correlated to size. GH increased IGF‐I plasma levels in the Namsen strain inspite of liver IGF‐I mRNA levels being lower in GH‐treated fish.