bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupling inter‐patch movement models and landscape graph to assess functional connectivity
Authors: Bergerot Benjamin , Tournant Pierline , Moussus Jean‐Pierre , Stevens Virginie‐M. , Julliard Romain , Baguette Michel , Foltête Jean‐Christophe
Published: November 2012

Landscape connectivity is a key process for the functioning and persistence of spatially‐structured populations in fragmented landscapes. Butterflies are particularly sensitive to landscape change and are excellent model organisms to study landscape connectivity. Here, we infer functional connectivity from the assessment of the selection of different landscape elements in a highly fragmented landscape in the Île‐de‐France region (France). Firstly we measured the butterfly preferences of the Large White butterfly (Pieris brassicae) in different landscape elements using individual release experiments. Secondly, we used an inter‐patch movement model based on butterfly choices to build the selection map of the landscape elements to moving butterflies. From this map, functional connectivity network ofP. brassicaewas modelled using landscape graph‐based approach. In our study area, we identified nine components/groups of connected habitat patches, eight of them located in urbanized areas, whereas the last one covered the more rural areas. Eventually, we provided elements to validate the predictions of our model with independent experiments of mass release‐recapture of butterflies. Our study shows (1) the efficiency of our inter‐patch movement model based on species preferences in predicting complex ecological processes such as dispersal and (2) how inter‐patch movement model results coupled to landscape graph can assess landscape functional connectivity at large spatial scales.
Respiratory and sleep disorders in mucopolysaccharidosis
Authors: Berger Kenneth I. , Fagondes Simone C. , Giugliani Roberto , Hardy Karen A. , Lee Kuo Sheng , McArdle Ciarán , Scarpa Maurizio , Tobin Martin J. , Ward Susan A. , Rapoport David M.
Published: November 2012

MPS encompasses a group of rare lysosomal storage disorders that are associated with the accumulation of glycosaminoglycans (GAG) in organs and tissues. This accumulation can lead to the progressive development of a variety of clinical manifestations. Ear, nose, throat (ENT) and respiratory problems are very common in patients with MPS and are often among the first symptoms to appear. Typical features of MPS include upper and lower airway obstruction and restrictive pulmonary disease, which can lead to chronic rhinosinusitis or chronic ear infections, recurrent upper and lower respiratory tract infections, obstructive sleep apnoea, impaired exercise tolerance, and respiratory failure. This review provides a detailed overview of the ENT and respiratory manifestations that can occur in patients with MPS and discusses the issues related to their evaluation and management.
Parental social support, coping strategies, resilience factors, stress, anxiety and depression levels in parents of children with MPS III (Sanfilippo syndrome) or children with intellectual disabilities (ID)
Authors: Grant Sheena , Cross Elaine , Wraith James Edmond , Jones Simon , Mahon Louise , Lomax Michelle , Bigger Brian , Hare Dougal
Published: November 2012

Mucopolysaccharidosis type III (MPS III, Sanfilippo syndrome) is a lysosomal storage disorder, caused by a deficiency in one of four enzymes involved in the catabolism of the glycosaminoglycan heparan sulphate. It is a degenerative disorder, with a progressive decline in children's intellectual and physical functioning. There is currently no cure for the disorder. To date there is a paucity of research on how this disorder impacts parents psychological functioning. Specifically, research in the area has failed to employ adequate control groups to assess if the impact of this disorder on parents psychological functioning differs from parenting a child with intellectual disability (ID). The current study examined child behaviour and parental psychological functioning in 23 parents of children with MPS III and 23 parents of children with ID. Parents completed postal questionnaires about their child's behaviour and abilities and their own psychological functioning. Parents of children with MPS III reported fewer behavioural difficulties as their child aged, more severe level of intellectual disability, and similar levels of perceived social support, coping techniques, stress, anxiety and depression levels as parents of children with ID. Both groups of parents scored above the clinical cut off for anxiety and depression. Parents of children with MPS III rated themselves as significantly less future‐orientated and goal directed than parents of children with ID. Services should develop support packages for parents of children with MPS III that incorporate an understanding of the unique stressors and current‐difficulty approach of this population. Future research should examine gender differences between parental psychological functioning, using mixed qualitative and quantitative approaches, and utilise matched developmental level and typically developing control groups.
Biomarker evidence for uncoupling of amyloid build‐up and toxicity in Alzheimer's disease
Authors: Zetterberg Henrik , Blennow Kaj
Published: November 2012

Certain preparations of Alzheimer‐associated amyloid beta (Aβ) exhibit rapid (within minutes) synaptotoxicity when applied to hippocampal slices or neuronal cell cultures, or when injected into the central nervous system of rodents. In addition, it is well known that some elderly people have brain amyloidosis without showing signs of cognitive impairment or neurodegeneration beyond the age norm. Biomarkers, reviewed extensively in a recent Perspectives article in Alzheimer's & Dementia, suggest that amyloid‐positive individuals are at higher risk of Alzheimer's disease than similarly aged individuals without evidence of brain amyloidosis, provided they live long enough. But how can the brain resist amyloid pathology for many years? Here, we expand on recent biomarker studies suggesting that Aβ build‐up and toxicity may occur in two phases. We hypothesize that the first phase may involve an autocatalytic build‐up of a nontoxic Aβ reservoir, tentatively named the AβCat pool, and that gain of toxicity may require brain incubation of Aβ in the water‐deprived plaque milieu over years to produce modified forms of the protein that are truly neurotoxic (AβTox). We argue for the need to describe the molecular natures of AβCat and AβTox in greater detail as a means to gain success in anti‐Aβ disease‐modifying drug development.
Aβ amyloid, cognition, andAPOEgenotype in healthy older adults
Authors: Lim Yen Ying , Ellis Kathryn A. , Ames David , Darby David , Harrington Karra , Martins Ralph N. , Masters Colin L. , Rowe Christopher , Savage Greg , Szoeke Cassandra , Villemagne Victor L. , Maruff Paul ,   AIBL Research Group
Published: November 2012

Background

Only one study has investigated the relationship between cerebral β‐amyloid (Aβ), apolipoprotein E (APOE) ɛ4 genotype, and cognition. Although significant relationships between cerebral Aβ and cognition were observed in ɛ4 carriers but not noncarriers, the magnitude of this relationship was not reported. Further, when demographic variables were controlled, the influence ofAPOEɛ4 on the relationship between cerebral Aβ and cognition dissipated.

Methods

In 144 healthy older adults who had undergone amyloid scanning andAPOEɛ4 genotyping in the Australian Imaging, Biomarkers, and Lifestyle (AIBL) Flagship Study of Ageing, correlations were conducted to determine the magnitude of relationship between cerebral Aβ and cognition in ɛ4 carriers and noncarriers. Fisher'sZwas used to compare these correlations and Cohen'sq determined the magnitude of difference between correlations.

Results

Cerebral Aβ was significantly associated with tasks of visual and verbal episodic memory inAPOEɛ4 carriers. This association was not observed in ɛ4 noncarriers. The relationship between cerebral Aβ and episodic memory in ɛ4 carriers was significantly different from that in ɛ4 noncarriers, and the magnitude of this difference was small to moderate.

Conclusions

InAPOEɛ4 carriers, there is a moderate negative relationship between cerebral Aβ and episodic memory. This suggests that increased cerebral Aβ may signify the onset of preclinical AD, especially in healthy older adults who are genetically at risk for AD.
Dose–response to 3 months of quercetin-containing supplements on metabolite and quercetin conjugate profile in adults
Authors: Cialdella-Kam Lynn , Nieman David C. , Sha Wei , Meaney Mary Pat , Knab Amy M. , Shanely R. Andrew
Published: November 2012

Quercetin, a flavonol in fruits and vegetables, has been demonstrated to have antioxidant, anti-inflammatory and immunomodulating influences. The purpose of the present study was to determine if quercetin, vitamin C and niacin supplements (Q-500 = 500 mg/d of quercetin, 125 mg/d of vitamin C and 5 mg/d of niacin; Q-1000 = 1000 mg/d of quercetin, 250 mg/d of vitamin C and 10 mg/d of niacin) would alter small-molecule metabolite profiles and serum quercetin conjugate levels in adults. Healthy adults (fifty-eight women and forty-two men; aged 40–83 years) were assigned using a randomised double-blinded placebo-controlled trial to one of three supplement groups (Q-1000, Q-500 or placebo). Overnight fasted blood samples were collected at 0, 1 and 3 months. Quercetin conjugate concentrations were measured using ultra-performance liquid chromatography (UPLC)-MS/MS, and metabolite profiles were measured using two MS platforms (UPLC-quadrupole time-of-flight MS (TOFMS) and GC-TOFMS). Statistical procedures included partial least square discriminant analysis (PLS-DA) and linear mixed model analysis with repeated measures. After accounting for age, sex and BMI, quercetin supplementation was associated with significant shifts in 163 metabolites/quercetin conjugates (false discovery rate,P< 0·05). The top five metabolite shifts were an increase in serum guaiacol, 2-oxo-4-methylthiobutanoic acid, allocystathionine and two bile acids. Inflammatory and oxidative stress metabolites were not affected. PLS-DA revealed a clear separation only between the 1000 mg/d and placebo groups (Q2Y= 0·763). The quercetin conjugate, isorhamnetin-3-glucuronide, had the highest concentration at 3 months followed by quercetin-3-glucuronide, quercetin-3-sulphate and quercetin diglucuronide. In human subjects, long-term quercetin supplementation exerts disparate and wide-ranging metabolic effects and changes in quercetin conjugate concentrations. Metabolic shifts were apparent at the 1000 mg/d dose; further research is required to understand the health implications of these shifts.
Kiwifruit consumption favourably affects plasma lipids in a randomised controlled trial in hypercholesterolaemic men
Authors: Gammon Cheryl S. , Kruger Rozanne , Minihane Anne M. , Conlon Cathryn A. , von Hurst Pamela R. , Stonehouse Welma
Published: November 2012

The unique composition of green kiwifruit has the potential to benefit CVD risk. The aim of the present study was to investigate the effect of consuming two green kiwifruits daily in conjunction with a healthy diet on plasma lipids and other metabolic markers and to examine response according toAPOEgenotype in hypercholesterolaemic men. After undergoing a 4-week healthy diet, eighty-five hypercholesterolaemic men (LDL-cholesterol (LDL-C) >3·0 mmol/l and TAG < 3 mmol/l) completed an 8-week randomised controlled cross-over study of two 4-week intervention sequences of two green kiwifruits per d plus healthy diet (intervention) or healthy diet alone (control). Anthropometric measures, blood pressure (BP) and fasting blood samples (plasma lipids, serum apoA1 and apoB, insulin, glucose, high-sensitivity C-reactive protein (hs-CRP)) were taken at baseline, and at 4 and 8 weeks. After the kiwifruit intervention, plasma HDL-cholesterol (HDL-C) concentrations were significantly higher (mean difference 0·04; 95 % CI 0·01, 0·07 mmol/l;P= 0·004) and the total cholesterol (TC):HDL-C ratio was significantly lower (mean difference − 0·15; 95 % CI − 0·24, − 0·05 mmol/l;P= 0·002) compared with the control. In carriers of theAPOE4allele, TAG decreased significantly (mean difference − 0·18; 95 % CI − 0·34, − 0·02 mmol/l;P= 0·03) with kiwifruit compared with control. There were no significant differences between the two interventions for plasma TC, LDL-C, insulin, glucose, hs-CRP and BP. The small but significant increase in HDL-C and decrease in TC:HDL-C ratio and TAG (inAPOE4carriers) suggest that the regular inclusion of green kiwifruit as part of a healthy diet may be beneficial in improving the lipid profiles of men with high cholesterol.
Testing Models of Distributive Politics using Exit Polls to Measure Voters’ Preferences and Partisanship
Authors: Larcinese Valentino , Snyder James M. , Testa Cecilia
Published: November 2012

This article tests several hypotheses about distributive politics by studying the distribution of federal spending across US states over the period 1978–2002. It improves on previous work by using survey data to measure the share of voters in each state that are Democrats, Republicans and Independents, or liberals, conservatives and moderates. No evidence is found that the allocation of federal spending to the states is distorted by strategic manipulation to win electoral support. States with many swing voters are not advantaged compared to states with more loyal voters, and ‘battleground states’ are not advantaged compared to other states. Spending appears to have little or no effect on voters’ choices, while partisanship and ideology have large effects.
Association of C-reactive protein and interleukin-6 with new-onset fatigue in the Whitehall II prospective cohort study
Authors: Cho H. J. , Kivimäki M. , Bower J. E. , Irwin M. R.
Published: November 2012

Background

Although basic research on neuroimmune interactions suggests that inflammatory processes may play a role in the development of fatigue, population-based evidence on this association is limited. This study examined whether plasma C-reactive protein (CRP) and interleukin-6 (IL-6), biomarkers of systemic inflammation, predict fatigue onset.

Method

The Whitehall II study is a large-scale cohort study conducted in 20 civil service departments in London. Plasma CRP and IL-6 were measured in 4847 non-fatigued participants at phase 3 (1991–1993, aged 39–63 years). Fatigue was assessed using the Vitality subscale of the 36-item Short Form Health Survey (SF-36) at phase 3 and phase 4 (1995–1996).

Results

During a mean follow-up of 3.1 years, 957 new fatigue cases (19.7%) were identified using the pre-established cut-off score of ⩽50 on the Vitality subscale. CRP values were dichotomized as low (<1.0 mg/l ) or high (⩾1.0 mg/l) using the Centers for Disease Control/American Heart Association recommendations. Similarly, IL-6 values were also dichotomized as low (<1.5 pg/ml) or high (⩾1.5 pg/ml). After full adjustment for sociodemographic and biobehavioral covariates, the odds ratios for new-onset fatigue were 1.28 [95% confidence interval (CI) 1.09–1.49,p = 0.003] for high CRP and 1.24 (95% CI 1.06–1.45,p = 0.008) for high IL-6. Similar results were found when CRP and IL-6 were treated as continuous variables.

Conclusions

Plasma CRP and IL-6 were prospectively associated with new-onset fatigue, supporting the hypothesis that low-grade inflammation has a role in the development of fatigue.
“Naturals of This Republic:” Slave Law, Sovereignty, and the Legal Politics of Citizenship in the Río de la Plata Borderlands, 1845–1864
Authors: Younger Joseph P.
Published: November 2012

In 1859, Cándido Xavier Azambuja appeared before officials in Salto, Uruguay demanding the return of an alleged fugitive slave, Pedro, pursuant to the terms of the 1851 Extradition Treaty between Brazil and Uruguay. According to Cándido's testimony, Pedro had fled from his brother Geronimo'sestancialocated near the Brazilian town of Bagé close to the Uruguayan border. Upon questioning, Cándido admitted that Pedro and Geronimo had been in the Estado Oriental briefly in 1851 in order to drive several herds of cattle back into Brazil, but argued that Pedro returned with his master and had never been to the Uruguayan Republic before or since. In response, Pedro argued that he was not a fugitive Brazilian slave, but rather a “natural of this republic.” Pedro claimed that he was born in Tacuarembó, Uruguay, and promptly produced the baptismal records to prove it. Pedro went on to note that his entire family consisted of free Uruguayans like himself. He then claimed that Cándido had repeatedly attempted “to make him a slave,” going so far as to remove him forcibly from his home and carry him across the border into Brazil. He requested protection from these continued threats to his and his family's basic rights under Uruguayan law.
Commercial Forms and Legal Norms in the Jewish Community of Medieval Egypt
Authors: Ackerman-Lieberman Phillip I.
Published: November 2012

Scholars agree that medieval Jewish legal writers responded to “the needs of the times” in making their legal rulings, carefully choosing the legal sources and precedents upon which they relied, rereading or even rejecting those sources in light of their quotidian reality. Particularly in the Geonic Period, as Talmudic norms encountered a geographically expansive community experiencing radical social transformations in the engagement with Islam, as well as rapid economic development concomitant with the rise of the ʿAbbāsids, which urbanized and transformed the economic life of the Jewish community, classical sources of Jewish law faced new pressures. Geonic leaders responded to these pressures by making recourse to the traditional institutions oftaqqana(Hebrew, “legislative enactment”) andminhag(Hebrew, “custom”). Therefore, it is widely accepted that the vicissitudes of daily life influenced both the responsa of the Geonim and their contributions to the expanding codificatory literature. On the other hand, the potential influence of Jewish legal norms upon daily life remains an unsettled area in the study of the history of the premodern Jewish community. A paucity of documentary or archaeological evidence complicates this problem, and edited literary texts of various genres remain themselves among the most important witnesses to Jewish life in the period.
Serotype distribution and characteristics of antimicrobial resistance inShigellaisolated from Henan province, China, 2001–2008
Authors: YANG H. , SUN W. , DUAN G. , ZHU J. , ZHANG W. , XI Y. , FAN Q.
Published: November 2012

The serotype distribution and susceptibility to 14 antimicrobial agents of 526 isolates ofShigellaspp. from four hospitals in Sun county, Henan province, China during 2001–2008, were analysed to identify associations of serotypes with resistance trends.S.flexneriwas the most frequent species (92·4%), the remainder wasS.sonnei. The prevalent serotype ofS.flexneriwas 2a (26·7%). Almost all (>99%) isolates were resistant to tetracycline, nalidixic acid and pipemidic acid; >80% were resistant to chloramphenicol, amoxicillin and co-trimoxazole but less than 5% were resistant to polymyxin B, furazolidone, cefotaxime and gentamicin.S.flexnerishowed statistically significant higher resistance thanS.sonneito amoxicillin, ampicillin, chloramphenicol and ciprofloxacin but resistance to co-trimoxazole was more common inS.sonneithan inS.flexneri. These results emphasize that monitoring of emerging resistance inShigellaisolates is essential for timely and appropriate recommendations for antimicrobial therapy.
Changes in body mass in later life and incident dementia
Authors: Power Brian D. , Alfonso Helman , Flicker Leon , Hankey Graeme J. , Yeap Bu B. , Almeida Osvaldo P.
Published: November 2012

Background: There is ongoing debate about whether a decline in body mass represents a true risk factor for dementia, whether it is a phenotypic marker of incipient dementia, or perhaps a marker of another process that increases dementia risk. This study was designed to determine if changes in body mass index (BMI) in later life are associated with hazard of incident dementia over a follow-up period of up to eight years.

Methods: Method followed was a prospective cohort study of 4,181 men aged 65–84 years, resident in Perth, Australia. The exposure of interest was change in BMI measured between 1996–1998 and 2001–2004. The outcome was incident dementia, established using the Western Australia Data Linkage System until 2009. We used Cox regression models to establish crude and adjusted hazard of dementia for change in BMI.

Results: Compared with men with a stable BMI, those with a decrease in BMI >1 kg/m2 had a higher adjusted hazard of dementia (hazard ratio (HR) = 1.89, 95% CI = 1.32–2.70). The cumulative hazard of dementia over follow-up for changes in BMI was greatest for men with a decrease in BMI >1 kg/m2; this trend was apparent for men in all BMI categories (underweight, normal, overweight, obese). A reverse “J-shaped” association between BMI change and incident dementia was observed, with the lowest dementia rate being for men whose BMI remained stable.

Conclusions: Men who maintained a stable body mass had the lowest incidence of dementia. Further studies are needed to clarify causality and assess feasibility of interventional studies to preserve body mass in aging men.
Clinical Skill and Knowledge Requirements of Health Care Providers Caring for Children in Disaster, Humanitarian and Civic Assistance Operations: An Integrative Review of the Literature
Authors: Johnson Heather L. , Gaskins Susan W. , Seibert Diane C.
Published: November 2012

Introduction

Military health care providers (HCPs) have an integral role during disaster, humanitarian, and civic assistance (DHCA) missions. Since 50% of patients seen in these settings are children, military providers must be prepared to deliver this care.

Purpose

The purpose of this systematic, integrative review of the literature was to describe the knowledge and clinical skills military health care providers need in order to provide care for pediatric outpatients during DHCA operations.

Data Sources

A systematic search protocol was developed in conjunction with a research librarian. Searches of PubMed and CINAHL were conducted using terms such as Disaster*, Geological Processes, and Military Personnel. Thirty-one articles were included from database and manual searches.

Conclusions

Infectious diseases, vaccines, malnutrition, sanitation and wound care were among the most frequently mentioned of the 49 themes emerging from the literature. Concepts included endemic, environmental, vector-borne and vaccine-preventable diseases; enhanced pediatric primary care; and skills and knowledge specific to disaster, humanitarian and civic assistance operations.

Implications for Practice

The information provided is a critical step in developing curriculum specific to caring for children in DHCA. While the focus was military HCPs, the knowledge is easily translated to civilian HCPs who provide care to children in these situations.

JohnsonHL,GaskinsSW,SeibertDC.Clinical skill and knowledge requirements of health care providers caring for children in disaster, humanitarian and civic assistance operations: an integrative review of the literature.Prehosp Disaster Med.2013;28(1):1-8.
The concept of the civilian: legal recognition, adjudication and the trials of international criminal justice
Authors: Garbett Claire
Published: November 2012

Contemporary initiatives to address civilian victimisation in armed conflict increasingly focus on international criminal justice institutions, rules and practices. These institutions are now expected to construct legal recognition of civilian victims of armed conflict, as well as prosecute the perpetrators. This article uses a case-study of theProsecutor v. Dragomir Miloševićheard by the International Criminal Tribunal for the former Yugoslavia to explore the concept of the civilian. It first examines the international legal frameworks and obligations that enforce the protection of civilians. It then explores the concept of the civilian as defined by the rules of humanitarian law, and the different approaches to defining civilians utilised by the parties to the Milošević trial. The article argues that the current ‘negative’ definition of civilians creates significant difficulties for understanding civilians as a distinct category of persons, and does not adequately capture their choices, actions and experiences in armed conflict.
The role of cognitive functioning in the outcome of those at clinical high risk for developing psychosis
Authors: Addington J. , Barbato M.
Published: November 2012

Although it is well established that cognitive impairment is a common feature of schizophrenia, only recently has cognitive functioning been prospectively studied in individuals at clinical high risk (CHR) for developing psychosis. To date, both cross-sectional and longitudinal studies have been conducted in the CHR population and in the context of later conversion to psychosis. A comprehensive review of the literature suggests that CHR individuals have general and specific baseline cognitive deficits compared to healthy controls. As a group, their cognitive course, tends to remain stable over time and in this way does not differ from healthy controls. For those who go on to develop a full-blown psychotic illness compared to those who do not convert, there appeared to be minimal differences at baseline with respect to cognition, although over time the converters may show deterioration in certain cognitive abilities compared to the non-converters. However, for many cognitive domains results are mixed, and may result from methodological limitations.
Incentives and Alternative Rating Approaches
Authors: Jelley R. Blake , Goffin Richard D. , Powell Deborah M. , Heneman Robert L.
Published: November 2012

Ratings of others’ performance are central in applied psychology. We investigated rater incentives and two approaches to Behavior Observation Scale (BOS) rating on rating accuracy. Raters (N = 147) were randomly assigned to one of three accuracy-incentive conditions and completed one of two BOSs 48 hr after observing videotaped performances. A serial BOS asked raters to assess one ratee at a time, across behaviors. A parallel BOS had raters consider all ratees on one behavior at a time. The serial (one ratee at a time) approach was generally more accurate than the parallel (one behavior at a time) approach. However, an accuracy incentive prior to observation mitigated the negative effects of the parallel approach. Overall, a serial BOS seems well suited for developmental appraisal.
Examining the Impact of Socialization Through Trust
Authors: Scott Kristyn A. , Montes Samantha D. , Gregory Irving P.
Published: November 2012

Past research on newcomer socialization practices has focused on how such practices influence employee attitudes through increased job knowledge and role clarity. However, to date, no research has examined organizational trust as a mechanism through which socialization influences employee attitudes. We suggest that socialization serves as a signal to new employees regarding the treatment they are likely to receive from the organization, thus leading to increased organizational trust and positive job attitudes. In this three-wave study, we examine the relations among institutionalized socialization, organizational trust, and job attitudes. Our results indicate that trust functions as a mediator between institutionalized socialization tactics and job satisfaction and affective commitment.
Employee Absence and Organizational Commitment
Authors: Woods Stephen A. , Poole Rebecca , Zibarras Lara D.
Published: November 2012

This study examined the relations of organizational commitment and demographic factors with objectively measured absence frequency data of 106 staff at a UK school, collected over a 1-year period. We found significant associations of commitment and absenteeism, with high affective and normative commitment, and low continuance commitment being associated with lower levels of absence. Age moderated two of these associations, with low normative commitment and high continuance commitment predicting absence most strongly for older workers. Our findings help practitioners and researchers to understand how commitment may interact with other factors to predict absence. Interaction effects in our data showed that absence frequencies tended to be highest for older workers who felt a lower sense of obligation to their organization, or a lack of alternatives to their present employment.
Long‐term variation in the cloud‐tracked zonal velocities at the cloud top of Venus deduced from Venus Express VMC images
Authors: Kouyama Toru , Imamura Takeshi , Nakamura Masato , Satoh Takehiko , Futaana Yoshifumi
Published: November 2012

We present observational evidence of the variation of the cloud‐tracked zonal velocity by ~20 m s–1 with a timescale of a few hundred days in the southern low latitude region based on an analysis of cloud images taken by the Venus Monitoring Camera on board Venus Express. A spectral analysis suggests that the variation has a periodicity with a period of about 255 days. Although cloud features are not always passive tracers, the periodical variation of the dynamical state is a robust feature. Superposed on this long‐term variation of the zonal velocity, Kelvin wave‐like disturbances tend to be observed in periods of relatively slow background velocity, while Rossby wave‐like disturbances tend to be observed in periods of fast background velocity. Since the momentum deposition by these waves can accelerate and decelerate the mean flow, these waves may contribute to the suggested long‐term oscillation.
Hydrated minerals on Endeavour Crater's rim and interior, and surrounding plains: New insights from CRISM data
Authors: Noe Dobrea E. Z. , Wray J. J. , Calef F. J. , Parker T. J. , Murchie S. L.
Published: November 2012

We have conducted a spectroscopic analysis of the rim and interior of Endeavour Crater using CRISM data in order to further constrain the mineralogical variability in the area and to identify targets of interest for in‐situanalysis by Opportunity. Our analysis reveals that the spectral character of both the sulfates and the phyllosilicates in the area is more diverse than has been reported to date, with phyllosilicates present on the rim and interior of Endeavour crater as well as on the surrounding plains. Spectra of the sulfates adjacent to the rim and in the crater's interior mound exhibit features that are consistent with a component of Ca‐sulfates. The spectral character of the phyllosilicates is consistent with that of Fe/Mg smectites, but there are clear spectral differences between the rim and interior phyllosilicates. Specifically, the phyllosilicates found inside the crater exhibit shallower, more rounded Fe/Mg‐OH bands, a subtle 1.9μm hydration band, and a strong 1–2 μm spectral slope relative to the phyllosilicates on the rim, suggesting that they have experienced modification relative to the rim phyllosilicates. This modification may be attributed either to alteration via acidic leaching or to dehydration. Stratigraphically, we find that these altered phyllosilicates unconformably overlie the sulfate‐bearing mound material, suggesting that they were emplaced by the reworking of rim phyllosilicates after the interior mound had reached its present day form.
Effects of stratospheric sulfate aerosol geo‐engineering on cirrus clouds
Authors: Kuebbeler Miriam , Lohmann Ulrike , Feichter Johann
Published: November 2012

Cooling the Earth through the injection of sulphate into the stratosphere is one of the most discussed geo‐engineering (GE) schemes. Stratospheric aerosols can sediment into the troposphere, modify the aerosol composition and thus might impact cirrus clouds. We use a global climate model with a physically based parametrization for cirrus clouds in order to investigate possible microphysical and dynamical effects. We find that enhanced stratospheric aerosol loadings as proposed by several GE approaches will likely lead to a reduced ice crystal nucleation rate and thus optically thinner cirrus clouds. These optically thinner cirrus clouds exert a strong negative cloud forcing in the long‐wave which contributes by 60% to the overall net GE forcing. This shows that indirect effects of stratospheric aerosols on cirrus clouds may be important and need to be considered in order to estimate the maximum cooling derived from stratospheric GE.
Assessment of fine‐scale parameterizations of turbulent dissipation rates near mixing hotspots in the deep ocean
Authors: Hibiya Toshiyuki , Furuichi Naoki , Robertson Robin
Published: November 2012

Shear‐based and/or strain‐based fine‐scale parameterizations of turbulent dissipation rates in the deep ocean become erroneous near topographic features where internal wave spectra deviate from Garrett‐Munk (GM). Although the Gregg‐Henyey‐Polzin (GHP) parameterization incorporates this spectral deviation, the applicability remains uncertain. We evaluate “α” and “β” representing the local internal wave energy in the high frequency (2f < ω < N) and low frequency (f < ω < 2f) bands, respectively, scaled by their corresponding values in GM using fine‐scale vertical shear and strain simultaneously measured near mixing hotspots. The local internal wave spectra are biased toward higher frequencies (α/β ≫ 1) over rough bathymetry where high frequency internal waves are generated, whereas they are biased toward lower frequencies (α/β≪ 1) at latitudes where high vertical wavenumber, near‐inertial shears are created byparametric subharmonic instabilities. Compared with the shear‐based and/or strain‐based parameterizations, GHP more accurately estimates turbulent dissipation rates by compensating for deviations from GM.
Stability of the regional stress field in central Japan during the late Quaternary inferred from the stress inversion of the active fault data
Authors: Tsutsumi Hiroyuki , Sato Katsushi , Yamaji Atsushi
Published: November 2012

We analyzed 169 geological fault‐slip data from 37 active faults in central Japan to investigate the late Quaternary stress field stability. Modern stress states have been documented with unprecedented accuracy; however, their stability over time scales beyond instrumental observations is inadequately understood. Because the stress field has changed in the geological past, we compared present stress conditions in central Japan, determined from geophysical observations, with conditions determined by inverting the fault‐slip data from active faults that exhibited cumulative displacement for the past ∼105years. The maximum stress axis obtained from fault‐slip data trends ESE–WNW. This state of stress accounts for 97% of the data and supports the fact that oblique faults with reverse and strike‐slip senses are interlaced in the region. The optimal stress is similar to the present stress state, indicating that the stress field in central Japan has been uniform and stable over the past ∼105 years.
Active tectonics of northwestern U.S. inferred from GPS‐derived surface velocities
Authors: McCaffrey Robert , King Robert W. , Payne Suzette J. , Lancaster Matthew
Published: November 2012

Surface velocities derived from GPS observations from 1993 to 2011 at several hundred sites across the deforming northwestern United States are used to further elucidate the region's active tectonics. The new velocities reveal that the clockwise rotations, relative to North America, seen in Oregon and western Washington from earlier GPS observations, continue to the east to include the Snake River Plain of Idaho and south into the Basin and Range of northern Nevada. Regional‐scale rotation is attributed to gravitationally driven extension in the Basin and Range and Pacific‐North America shear transferred through the Walker Lane belt aided by potentially strong pinning below the Idaho Batholith. The large rotating section comprising eastern Oregon displays very low internal deformation rates despite seismological evidence for a thin crust, warm mantle, organized mantle flow, and elevated topography. The observed disparity between mantle and surface kinematics suggests that either little stress acts between them (low basal shear) or that the crust is strong relative to the mantle. The rotation of the Oregon block impinges on Washington across the Yakima fold‐thrust belt where shortening occurs in a closing‐fan style. Elastic fault locking at the Cascadia subduction zone is reevaluated using the GPS velocities and recently published uplift rates. The 18 year GPS and 80 year leveling data can both be matched with a common locking model suggesting that the locking has been stable over many decades. The rate of strain accumulation is consistent with hundreds of years between great subduction events.
Influence of subglacial conditions on ice stream dynamics: Seismic and potential field data from Pine Island Glacier, West Antarctica
Authors: Smith Andrew M. , Jordan Tom A. , Ferraccioli Fausto , Bingham Robert G.
Published: November 2012

We interpret seismic reflection and airborne potential field data acquired on Pine Island Glacier, West Antarctica and find variations in the subglacial geology which correlate with variations in ice dynamics. Immediately beneath the glacier is a mixture of soft, deforming sediments and harder, non‐deforming sediments. Beneath this, a sedimentary basin lies under part of the main glacier, with another under one of its slower‐moving tributaries. A tectonic boundary underlies the main trunk of the glacier separating these sedimentary basins to the north from crystalline rocks to the south, which also include a thick, rift‐related magmatic intrusion. The boundary correlates with changes in the basal roughness, ice flow speed, and basal drag. Smoother bed, faster flow, and lower basal drag characterize the thicker sedimentary sequences, to the north, but there is no corresponding lateral change in the acoustic properties of the bed. Changes in the sub‐bed (i.e., deeper than the ice‐bed interface) lithology appear to account for the contrasting basal drag and ice velocity patterns over the glacier. Subglacial erosion could remove a thin layer of soft sediments to the south of the geological boundary, leading to increased basal drag and reduced ice flow in the future. We conclude that the subglacial geology plays a significant role in controlling the spatial pattern of present‐day ice flow and that the consequences of subglacial erosion may be reflected in temporal changes to the ice dynamics in the past and perhaps also in the near future.
Impact of a new anisotropic rheology on simulations of Arctic sea ice
Authors: Tsamados M. , Feltham D. L. , Wilchinsky A. V.
Published: November 2012

A new rheology that explicitly accounts for the subcontinuum anisotropy of the sea ice cover is implemented into the Los Alamos sea ice model. This is in contrast to all models of sea ice included in global circulation models that use an isotropic rheology. The model contains one new prognostic variable, the local structure tensor, which quantifies the degree of anisotropy of the sea ice, and two parameters that set the time scale of the evolution of this tensor. The anisotropic rheology provides a subcontinuum description of the mechanical behavior of sea ice and accounts for a continuum scale stress with large shear to compression ratio and tensile stress component. Results over the Arctic of a stand‐alone version of the model are presented and anisotropic model sensitivity runs are compared with a reference elasto‐visco‐plastic simulation. Under realistic forcing sea ice quickly becomes highly anisotropic over large length scales, as is observed from satellite imagery. The influence of the new rheology on the state and dynamics of the sea ice cover is discussed. Our reference anisotropic run reveals that the new rheology leads to a substantial change of the spatial distribution of ice thickness and ice drift relative to the reference standard visco‐plastic isotropic run, with ice thickness regionally increased by more than 1 m, and ice speed reduced by up to 50%.
Quantification of floating macroalgae blooms using the scaled algae index
Authors: Garcia Rodrigo A. , Fearns Peter , Keesing John K. , Liu Dongyan
Published: November 2012

Quantifying the spatial coverage of floating macroalgae from satellite imagery, using methods such as the normalized difference vegetation index (NDVI) and the floating algae index (FAI), requires the use of a scene‐wide threshold to isolate and then compute the number of floating macroalgae pixels. The problem faced is the sensitivity of the NDVI and, to a lesser extent, the FAI to radiance contributions from atmospheric aerosols and turbid water. Both these factors can vary significantly across a satellites' field‐of‐view generating irregular apparent reflectance of ocean and floating macroalgae pixels across an NDVI/FAI scene, leading to inaccuracies in spatial coverage estimates. We present a simple image processing algorithm, termed the scaled algae index (SAI), that removes any variability present in ocean and floating macroalgae pixels in NDVI or FAI imagery. The SAI does this by subtracting a given pixel's index by that of a local ocean pixel, effectively scaling ocean pixels to values near zero, and macroalgae pixels to positive values. The SAI algorithm has been tested on NDVI and FAI scenes of the 2008/2009 floating macroalgae blooms that occurred in the Yellow Sea, China. These SAI images show a major reduction in variability with scene‐wide histograms being unimodal. Histogram analysis also indicates that sufficient contrast exists between ocean and floating macroalgae pixels to enable segmentation by a scene‐wide threshold. A semiautomated threshold determination procedure is also presented, which together with the SAI algorithm can be used to compute accurate estimates of the spatial coverage of floating macroalgae.
The Madagascar Bloom: A serendipitous study
Authors: Srokosz M. A. , Quartly G. D.
Published: November 2012

The late austral summer (February–April) phytoplankton bloom that occurs east of Madagascar exhibits significant interannual variability and at its largest extent covers ~1% of the world's ocean surface area. The bloom raises many intriguing questions about how it begins, is sustained, propagates to the east, exports carbon, and ends. It has been observed and studied using satellite ocean color observations, but the lack of in situ data makes it difficult to address these questions. Here we describe observations that were made serendipitously on a cruise in February 2005. These show clearly for the first time the simultaneous existence of a deep chlorophyll maximum at ~70–110 m depths (seen in SeaSoar fluorimeter data) and a surface chlorophyll signature [seen in Sea‐viewing Wide Field‐of‐view Sensor (SeaWiFS) satellite ocean color data]. The observations also show the modulation of the biological signature at the surface by the eddy field but not of the deep chlorophyll maximum. Trichodesmium dominates the bloom nearer to Madagascar, while the diatom Rhizosolenia clevei (and its symbiont Richelia intracellularis) dominates further from the island. The surface bloom seen in the SeaWiFS data is confined to the shallow (~30 m) mixed layer. It is hypothesized that the interannual variability in bloom intensity may be due to variations in coastal upwelling and thus the supply of iron, which is a micronutrient that can limit diazotroph growth.
A bending angle forward operator for global positioning system radio occultation measurements
Authors: Cucurull L. , Derber J. C. , Purser R. J.
Published: November 2012

Applications for space‐based GPS technology have extended to the atmospheric field during the last two decades. More recently, numerical weather prediction (NWP) centers started incorporating global positioning system (GPS) radio occultation (RO) soundings into their operational assimilation algorithms, resulting in a significant improvement in weather forecasting skill. The main reasons for such benefits are the unbiased nature of the GPS RO measurements, high accuracy and precision, all‐weather capability, and equal accuracy over either land or ocean. Profiles of refractivity or bending angle are typically used, owing to the relative simplicity of their forward operators and the computational economy this implies. Although the NOAA National Centers for Environmental Prediction (NCEP) are using refractivities in their operational configuration, a bending angle forward operator has been developed, tested, and implemented and was scheduled to replace the assimilation of refractivities operationally in May, 2012. Results from the NCEP's bending angle method (NBAM) show improvement over the assimilation of refractivities in all atmospheric fields being evaluated. A detailed description and evaluation of NBAM is presented in this article, as well as the advantages this code offers over the assimilation of refractivities and other existing algorithms that assimilate GPS RO bending angles.
Comprehensive evaluation of polar weather research and forecasting model performance in the Antarctic
Authors: Bromwich David H. , Otieno Francis O. , Hines Keith M. , Manning Kevin W. , Shilo Elad
Published: November 2012

Recent versions of the Polar Weather Research and Forecasting model are evaluated over the Antarctic to assess the impact of model improvements, resolution, large‐scale circulation variability, and uncertainty in initial and lateral boundary conditions. The model skill differs more between forecasts using different sources of lateral boundary data than between forecasts from different model versions or simulated years. Using the ERA‐Interim reanalysis for initial and lateral boundary conditions produces the best skill. The forecasts have a cold summer and a warm winter bias in 2 m air temperatures, with similar but smaller bias in dew point temperatures. Upper air temperature biases are small and remain less than 1 °C except at the tropopause in summer. Geopotential height biases increase with height in both seasons. Deficient downward longwave radiation in all seasons and an under representation of clouds enhance radiative loss, leading to the cold summer bias. Excess summer surface incident shortwave radiation plays a secondary role, because 80% of it is reflected, leading to greater skill for clear compared with cloudy skies. The positive wind speed bias produces a warm surface bias in winter resulting from anomalously large downward flux of sensible heat toward the surface. Low temperatures on the continent limit sublimation and hence the precipitable water amounts over the ice sheet. ERA‐Interim experiments with higher precipitable water showed reduced biases in downwelling shortwave and longwave radiation. Increasing horizontal resolution from 60 to 15 km improves the skill of surface wind forecasts.