bluuebunny/crossref_metadata_2025 huggingface dataset:
Short ensembles: an efficient method for discerning climate-relevant sensitivities in atmospheric general circulation models
Authors: Wan H. , Rasch P. J. , Zhang K. , Qian Y. , Yan H. , Zhao C.
Published: September 2014

Abstract. This paper explores the feasibility of an experimentation strategy for investigating sensitivities in fast components of atmospheric general circulation models. The basic idea is to replace the traditional serial-in-time long-term climate integrations by representative ensembles of shorter simulations. The key advantage of the proposed method lies in its efficiency: since fewer days of simulation are needed, the computational cost is less, and because individual realizations are independent and can be integrated simultaneously, the new dimension of parallelism can dramatically reduce the turnaround time in benchmark tests, sensitivities studies, and model tuning exercises. The strategy is not appropriate for exploring sensitivity of all model features, but it is very effective in many situations. Two examples are presented using the Community Atmosphere Model, version 5. In the first example, the method is used to characterize sensitivities of the simulated clouds to time-step length. Results show that 3-day ensembles of 20 to 50 members are sufficient to reproduce the main signals revealed by traditional 5-year simulations. A nudging technique is applied to an additional set of simulations to help understand the contribution of physics–dynamics interaction to the detected time-step sensitivity. In the second example, multiple empirical parameters related to cloud microphysics and aerosol life cycle are perturbed simultaneously in order to find out which parameters have the largest impact on the simulated global mean top-of-atmosphere radiation balance. It turns out that 12-member ensembles of 10-day simulations are able to reveal the same sensitivities as seen in 4-year simulations performed in a previous study. In both cases, the ensemble method reduces the total computational time by a factor of about 15, and the turnaround time by a factor of several hundred. The efficiency of the method makes it particularly useful for the development of high-resolution, costly, and complex climate models.
Postoperative Venous Thrombotic Events in Asian Elderly Patients with Surgically Treated Hip Fractures with and without Chemoprophylaxis
Authors: Wong Keng L. , Daruwalla Zubin J. , Lan Chester J.H. , Tan Si H.S. , Shen Liang , Chua Weiliang , Manohara Ruben , Lingaraj Krishna
Published: September 2014

Background and purpose

Chemothromboprophylaxis for hip fracture surgery has been under-practiced in Asia. We investigate the postoperative incidence of venous thrombotic events (VTE) in elderly Asian patients with hip fractures.

Patients and methods

Patients over 60 years old with surgically treated hip fractures were reviewed. All patients followed a hip fracture protocol, which included a post-operative ultrasound Doppler venous scan of both lower limbs five days after injury to detect any deep vein thrombosis (DVT). All patients were given mechanical prophylaxis. Patients who had additional chemoprophylaxis were included.

Results

From 2010 to 2012, 454 patients were reviewed. The overall incidence of DVT was 6.4% (29 patients). The incidence of PE was 1.3% (six patients). There was no significant correlation between DVT and age, gender, race, hypertension, diabetes mellitus, end stage renal failure, type of fracture and operation, preoperative haemoglobin, platelet count or urea and creatinine levels. Sixteen DVTs (55.2%) were on the ipsilateral side as the fracture, eight (27.6%) were on the contralateral side and five (17.2%) were bilateral. Chemoprophylaxis was not given to 399 patients, of which 27 (6.8%) developed DVT. Ten (2.5%) were proximal DVTs in which four (1%) developed PE. One (0.25%) patient developed PE without DVT. Fifty-five patients were on chemoprophylaxis, of which two (3.6%) developed DVT. Both were proximal DVTs with one subsequently developing PE.

Conclusions

The incidence of VTE in Asian patients may be lower compared to Western populations when mechanical prophylaxis is used. Chemoprophylaxis may assist in reducing the rates of DVT but not PE. The low incidence may not justify the use of routine chemoprophylaxis.
Delayed Diagnosis of Clear Cell Chondrosarcoma after Total Hip Replacement. A Case Report of a Rare Entity Encountered in Common Surgery
Authors: Liska Franz , Toepfer Andreas , Straub Melanie , Rechl Hans , von Eisenhart-Rothe Ruediger
Published: September 2014

We report the case of a young female patient who received a total hip replacement due to pain in her left hip joint, misdiagnosed as degenerative arthritis. A clear cell chondrosarcoma (CCCS) in the femoral head had initially not been detected. Seven years later, a periprosthetic recurrence of CCCS close to the former femoral osteotomy occurred. Although a sample of the periprosthetic tumour had been taken for histologic analysis, the recurrence of CCCS remained misdiagnosed for almost 2 years until this rare histopathologic morphology was examined in a specialised multidisciplinary tumour centre. Finally, revision surgery with wide tumour resection margins had to be performed requiring the removal of the total hip replacement and its reconstruction using a modular megaimplant (proximal femoral replacement). Relevant facts of the CCCS as a rare entity regarding histology, treatment and differential diagnoses are discussed.
Balloon Tamponade Repair after Inadvertent Subclavian Artery Catheterization
Authors: Dunham Gregor M. , Vaidya Sandeep S.
Published: September 2014

Purpose

The approach to repair inadvertent subclavian artery catheterization has evolved to increasingly less invasive modalities. Most recently, endovascular balloon tamponade has become the preferred initial approach. We report our experience and review the technique.

Methods

Eleven patients underwent primary treatment with balloon tamponade from 2001 to 2012. Using either femoral or brachial approach, an appropriately sized balloon was placed directly adjacent to the site of hemorrhage and inflated for 5-25 min on the basis of operator preference and repeated as needed. Primary technical success defined as hemostasis was achieved with balloon tamponade.

Results

Technical success was achieved in nine of 11 patients. The mean follow-up time was 10.8 months. Two deaths were reported, both unrelated to catheter placement and removal. Of the successful cases, five achieved hemostasis with one inflation and four required two inflations. One patient developed a small thrombus at the thyrocervical trunk of no clinical significance. No other complications occurred. One of the nine patients had a double wall injury. The two patients with unsuccessful hemostasis underwent two & four inflations, respectively. Both patients had a double wall injury. One of the patients had a complication of distal ischemia and stroke.

Conclusions

In patients with inadvertent subclavian artery catheterization, balloon tamponade is an effective first step in management, with primary technical success approaching 100% in cases of single lumen injury. It appears less effective in patients with double lumen injury. However, the ease of transition from balloon tamponade to stent placement supports an initial attempt at hemostasis with tamponade prior to placement of a permanent stent.
Two-stage Hemodialysis Reliable Outflow (HeRO) Graft Implantation Technique that Avoids the use of a Femoral Bridging Dialysis Catheter
Authors: Yoon William J. , Lorelli David R.
Published: September 2014

Purpose

The purpose of this study is to report a novel two-stage Hemodialysis Reliable Outflow (HeRO) graft implantation technique that avoids the use of a femoral bridging hemodialysis catheter in internal jugular vein (IJV) catheter-dependent patients with contralateral central venous occlusion.

Methods

The first stage is to implant the ePTFE component and consists of: 1) performing two to three incisions in the upper arm ipsilateral to the preexisting IJV catheter, 2) tunneling the expanded polytetrafluoroethylene (ePTFE) component through these incision sites, and 3) placing the ePTFE component in the subcutaneous tissue without anastomosing it to the target artery. The preexisting IJV catheter is maintained to provide continuous dialysis access. The second stage is initiated in 4 weeks and includes: 1) thrombectomy and anastomosing the ePTFE component arterial end to the target artery, 2) insertion of the venous outflow component using the preexisting IJV catheter access site, and 3) connecting the venous outflow component to the ePTFE component in the standard fashion.

Results

The HeRO graft was successfully implanted in two stages without using a femoral bridging catheter. Immediate postimplant cannulatabilty was achieved upon completion of the second stage procedure.

Conclusion

This novel two-stage HeRO implantation technique is simple, yet allows immediate cannulation upon completion of the second stage procedure while avoiding the need of a femoral bridging catheter in IJV catheter-dependent patients with contralateral central venous occlusion, and thus lowering the risk of infection related to a femoral bridging catheter.
Ineraction between some saprophytic and entomopathogenis fungi
Authors: Miętkiewski Ryszard
Published: September 2014

The studies on interactions between selected entomopathogenic fungi: Beaweria bassiana, Conidiobolus thromboides (= Entomophthora virulenta), Paecilomyces farinosus, Verticillium lecanii and four species of saprophytic fungi were carried out.
Collybia oedipus (Agaricales, Tricholomataceae)
Authors: Hołownia Irena
Published: September 2014

The materiał collected during two consecutive years (1984, 1985) in a deciduous, forest dominated by beech on very fertile soil in the Beskid Niski mts. exhibited a number of characteristics allowing to distinguish the variety oedipus (Quel.) from the group Collybia dryophila (Buli. ex Fr.) Kummer and definitely recognize it as a separate species, Collybia oedipus (Qućl.) Metrod, Hołownia em. now.
The sclerotium viability in several species of Typhula genus
Authors: Dynowska Maria
Published: September 2014

The aim of the experiment was to investigate the sclerotium vivacity in three fungus species: Typhula incarnata Lasch ex Fr., Typhula phacorrhiza Fr. and Typhula variabilis Riess.
Keratinophilous fungi in the sediments of the surface waters bottoms
Authors: Ulfig Krzysztof
Published: September 2014

The sediments of rivers, ponds, artificial lakes and sewage were examined for keratinophilic fungi. The depended on the degree of waters contamination with the communal and industrial sewage.
Growth of mycorrhizal fungi of pine (Pinus sylvestris L.) in associative cultures with Actinomycetes at different pH values
Authors: Kampert Maria
Published: September 2014

The effect of 5 actinomycete strains on growth of four mycorrhizal fungi of pine at different pH values was tested in laboratory media. Both inhibition and stimulation of growth was distinctly dependent upon the pH of the medium. In general the actinomycetes introduced to 7-days old fungal cultures more often stimulated than inhibited the fungi. This was not observed when the media were inoculated with both organisms simultaneously.
Mycoflora of sawn timbers in Benin City
Authors: Okhuoya J. A. , Itaman S. O.
Published: September 2014

In a fungal suryey of sawn timbers in scattared localities in Benin City, fungal species isolated were mainly members of Hyphomycetes, with few Ascomycetes and Basidiomycetes. Cellulolytic abilities of isolates were determined and found to be highest in a basidiomycete, Pleurotus ostreatus. The high incidence of these isolates was traced to the poor ventillation in the shades where the timbers arę sold and the high moisture content of timber before display for sale.
Mnohojazyčnost jako dílčí cíl výuky cizích jazyků a možnosti její podpory
Authors: Janík M.
Published: September 2014

Studie je věnována otázce mnohojazyčnosti jako dílčímu cíli jazykového vzdělávání. Záměrem autora je nabídnout čtenáři vhled do problematiky výuky dalších cizích jazyků ve škole v kontextu podpory mnohojazyčnosti. V první části textu vymezíme koncepci mnohojazyčnosti, kterou chápeme jako zastřešující teoretický rámec pro naše pojetí (tedy pojetí mnohojazyčnosti jako dílčího cíle výuky cizích jazyků). Protože mnohojazyčnost definujeme jako schopnost žáka ovládat alespoň tři jazyky, navrhneme v následující části, jak tyto jazyky označovat a řadit. V další části nahlédneme osvojování dalších (tedy druhých, třetích, čtvrtých…) cizích jazyků a jejich specifika. Ve čtvrté části se zaměříme na didaktické uchopení koncepce mnohojazyčnosti a na možnou implementaci podpory mnohojazyčnosti do výuky dalších cizích jazyků. V poslední části se zaměříme na učitele a na jeho kompetence, kterými by měl disponovat, aby mohl ve výuce cizích jazyků smysluplně podporovat mnohojazyčnost.
Soukromé doučování a vzdělávací politiky v Evropě
Authors: Šťastný V.
Published: September 2014

Cílem studie je identifikovat a zařadit vybrané evropské země do jednotlivých typů Brayovy typologie vzdělávacích politik ve vztahu k soukromému doučování (1999, 2009) a s využitím dostupných empirických studií představit zavedená opatření a jejich dopady. V první části příspěvku autor definuje soukromé doučování a jeho možné implikace pro formální vzdělávací systém a jeho spravedlnost. Ve druhé části autor představuje Brayovu typologii vzdělávacích politik ve vztahu k soukromému doučování a její vývoj v čase. Jednotlivé typy vzdělávacích politik jsou uvedeny na konkrétních příkladech evropských zemí. Ve třetí části je pak diskutována aktuální situace v České republice. V Evropě je možné identifikovat nejen země podporující soukromé doučování (Francie), ale i země tento fenomén do určité míry regulující (Litva, Německo, Slovensko), nebo i takové, které se k soukromému doučování staví nevšímavě (Chorvatsko). Uvedené příklady demonstrují různorodost podob stínového vzdělávacího systému v různých kontextech a dosavadní reakce tvůrců vzdělávací politiky na něj. Nezájem o tento fenomén v České republice ostře kontrastuje s doporučeními světových odborníků na tuto problematiku. Zároveň v našem kontextu chybí relevantní výzkumná data, o která by bylo možné opřít politické rozhodování.
Structural approaches for prevention of sexually transmitted HIV in general populations: definitions and an operational approach
Authors: Parkhurst Justin O
Published: September 2014

Introduction

Although biomedical HIV prevention efforts have seen a number of recent promising developments, behavioural interventions have often been described as failing. However, clear lessons have been identified from past efforts, including the need to address influential social, economic and legal structures; to tailor efforts to local contexts; and to address multiple influencing factors in combination. Despite these insights, there remains a pervasive strategy to try to achieve sexual behaviour change through single, decontextualized, interventions or sets of activities. With current calls for structural approaches to HIV as part of combination HIV prevention, though, there is a unique opportunity to define a structural approach to HIV prevention as one which moves beyond these past limitations and better incorporates our knowledge of the social world and the lessons from past efforts.

Discussion

A range of interlinked concepts require delineation and definition within the broad concept of a structural approach to HIV. This includes distinguishing between “structural factors,” which can be seen as any number of elements (other than knowledge) which influence risk and vulnerability, and “structural drivers,” which should be reserved for situations where an empirically established relationship to a target group is known. Operationalizing structural approaches similarly can take different paths, either working to alter structural drivers or alternatively working to build individual and community resilience to infection. A “structural diagnostic approach” is further defined as the process one undertakes to develop structural intervention strategies tailored to target groups.

Conclusions

For three decades, the HIV prevention community has struggled to reduce the spread of HIV through sexual risk behaviours with limited success, but equally with limited engagement with the lessons that have been learned about the social realities shaping patterns of sexual practices. Future HIV prevention efforts must address the multiple factors influencing risk and vulnerability, and they must do so in ways tailored to particular settings. Clarity on the concepts, terminology and approaches that can allow structural HIV prevention efforts to achieve this is therefore essential to improve the (social) science of HIV prevention.
A descriptive analysis of perceptions of HIV risk and worry about acquiring HIV among FEM‐PrEP participants who seroconverted in Bondo, Kenya, and Pretoria, South Africa
Authors: Corneli Amy L , McKenna Kevin , Headley Jennifer , Ahmed Khatija , Odhiambo Jacob , Skhosana Joseph , Wang Meng , Agot Kawango ,   for the FEM‐PrEP Study Group
Published: September 2014

Introduction

Risk perception is a core construct in many behaviour change theories in public health. Individuals who believe they are at risk of acquiring an illness may be more likely to engage in behaviours to reduce that risk; those who do not feel at risk may be unlikely to engage in risk reduction behaviours. Among participants who seroconverted in two FEM‐PrEP sites – Bondo, Kenya, and Pretoria, South Africa – we explored perceived HIV risk and worry about acquiring HIV prior to HIV infection.

Methods

FEM‐PrEP was a phase III clinical trial of once‐daily, oral emtricitabine and tenofovir disoproxil fumarate for HIV prevention among women in sub‐Saharan Africa. We asked all participants about their perceived HIV risk in the next four weeks, prior to HIV testing, during a quantitative face‐to‐face interview at enrolment and at quarterly follow‐up visits. Among participants who seroconverted, we calculated the frequencies of their responses from the visit conducted closest to, but before, HIV acquisition. Also among women who seroconverted, we conducted qualitative, semi‐structured interviews (SSIs) at weeks 1, 4 and 8 after participants’ HIV diagnosis visit to retrospectively explore feelings of HIV worry. Applied thematic analysis was used to analyse the SSI data.

Results

Among participants who seroconverted in Bondo and Pretoria, 52% reported in the quantitative interview that they had no chance of acquiring HIV in the next four weeks. We identified four processes of risk rationalization from the SSI narratives. In “protective behaviour,” participants described at least one risk reduction behaviour they used to reduce their HIV risk; these actions made them feel not vulnerable to HIV, and therefore they did not worry about acquiring the virus. In “protective reasoning,” participants considered their HIV risk but rationalized, based on certain events or beliefs, that they were not vulnerable and therefore did not worry about getting HIV. In “recognition of vulnerability,” participants described reasons for being worried about getting HIV but said no or limited action was taken to reduce their perceived vulnerability. Participants with “no rationalization or action” did not describe any HIV worry or did not engage in HIV risk reduction behaviours.

Conclusions

Women who are at substantial risk of acquiring HIV may underestimate their actual risk. Yet, others who accurately understand their HIV risk may be unable to act on their concerns. Perceived HIV risk and risk rationalization are important concepts to explore in risk reduction counselling to increase the use of HIV prevention strategies among women at risk of HIV.
Women and ARV‐based HIV prevention – challenges and opportunities
Authors: Geary Cynthia W , Bukusi Elizabeth A
Published: September 2014

ARV‐based HIV prevention methods available in pill, gel or ring formulations (broadly referred to as microbicides) offer the possibility of protection against HIV for women who find it difficult because they cannot ask their partners to use condoms or even refuse sex. Partial efficacy of ARV‐based medications has been demonstrated in a number of clinical trials around the world among various populations, building the evidence that ARV‐based technologies will contribute to reducing the AIDS epidemic worldwide. Disappointing results, however, from two trials in sub‐Saharan Africa, where poor adherence contributed to study closure due to futility, have raised questions about whether women at the centre of the epidemic are able to effectively use products that require routine use. Also, there are fears by some of risk compensation by decreased condom use because of the availability of microbicides when only partial efficacy has been demonstrated in microbicide trials to date. Of note, sub‐analyses of biologic measures of adherence in trials where this was possible have shown a strong correlation between good adherence and efficacy, reinforcing the necessity of good adherence. Research conducted in conjunction with clinical trials and post‐trials in advance of possible rollout of ARV‐based products have examined social and cultural factors, gender‐related and otherwise, influencing adherence and other aspects of women's use of products. These include HIV stigma, women's perception of risk, partner and community influences and the differing needs of women in various stages of life and in different circumstances. It is the purpose of this supplement to give voice to the needs of women who can benefit from woman‐initiated methods by presenting research results and commentary to contribute to the global conversation about optimizing women's experience with ARV‐based prevention.
Pvr expression regulators in equilibrium signal control and maintenance of Drosophila blood progenitors
Authors: Mondal Bama Charan , Shim Jiwon , Evans Cory J , Banerjee Utpal
Published: September 2014

Blood progenitors within the lymph gland, a larval organ that supports hematopoiesis in Drosophila melanogaster, are maintained by integrating signals emanating from niche-like cells and those from differentiating blood cells. We term the signal from differentiating cells the ‘equilibrium signal’ in order to distinguish it from the ‘niche signal’. Earlier we showed that equilibrium signaling utilizes Pvr (the Drosophila PDGF/VEGF receptor), STAT92E, and adenosine deaminase-related growth factor A (ADGF-A) (Mondal et al., 2011). Little is known about how this signal initiates during hematopoietic development. To identify new genes involved in lymph gland blood progenitor maintenance, particularly those involved in equilibrium signaling, we performed a genetic screen that identified bip1 (bric à brac interacting protein 1) and Nucleoporin 98 (Nup98) as additional regulators of the equilibrium signal. We show that the products of these genes along with the Bip1-interacting protein RpS8 (Ribosomal protein S8) are required for the proper expression of Pvr.
Availability restrictions and alcohol consumption: A case of restricted hours of alcohol sales in Russian regions
Authors: Kolosnitsyna Marina , Sitdikov Marat , Khorkina Natalia
Published: September 2014

Kolosnitsyna, M., Sitdikov, M., & Khorkina, N. (2014). Availability restrictions and alcohol consumption: A case of restricted hours of alcohol sales in Russian regions. The International Journal Of Alcohol And Drug Research, 3(3), 193 – 201. doi:http://dx.doi.org/10.7895/ijadr.v3i3.154Aim: To determine how new restrictions on hours of alcohol retail sales influence alcohol consumption in Russia.Design: Natural experiment with combined regional and micro-data.Setting/Participants: Cross-sectional samples from the Russian Longitudinal Monitoring Survey, corresponding to waves 18 and 19, years 2009–2010, 32 Russian regions and more than 7,000 adults (aged 15 and up) consuming alcohol at least once per month.Measures: Descriptive analysis of per capita alcohol sales at the regional level and regression analysis of pure spirit consumption at the individual level, controlling for various socioeconomic factors, including sales bans.Findings: We revealed a significant positive correlation between the amount of alcohol consumed and the number of hours of allowed alcohol sales when other factors were controlled. The results gained from analyzing the micro-data were confirmed using the regional sales information. In terms of drinking reduction, sales restrictions in the evening hours seem more efficient than restrictions in the morning hours. Restricted hours of sale do not increase consumption of beer or home-distilled alcohol.Conclusions: Alcohol consumption depends on the hours of sale, all else being equal. Restricting the legal hours of alcohol sales in Russian regions has the potential to reduce consumption levels. These findings indicate a need for a further reduction in sales hours in the regions where heavy drinking is especially widespread.
Moderating diets to feed the future
Authors: Davis Kyle F. , D'Odorico Paolo , Rulli Maria Cristina
Published: September 2014

Population growth, dietary changes, and increasing biofuel use are placing unprecedented pressure on the global food system. While this demand likely cannot be met by expanding agricultural lands, much of the world's cropland can attain higher crop yields. Therefore, it is important to examine whether increasing crop productivity to the maximum attainable yield (i.e., yield gap closure) alone can substantially improve food security at global and national scales. Here we show that closing yield gaps through conventional technological development (i.e., fertilizers and irrigation) can potentially meet future global demand if diets are moderated and crop‐based biofuel production is limited. In particular, we find that increases in dietary demand will be largely to blame should crop production fall short of demand. In converting projected diets to a globally adequate diet (3000 kcal/cap/d; 20% animal kcal) under current agrofuel use, we find that 1.8–2.6 billion additional people can be fed in 2030 and 2.1–3.1 billion additional people in 2050, depending on the extent to which yields can improve in those periods. Therefore, the simple combination of yield gap closure and moderating diets offers promise for feeding the world's population but only if long‐term sustainability is the focus.
Remote sensing of fugitive methane emissions from oil and gas production in North American tight geologic formations
Authors: Schneising Oliver , Burrows John P. , Dickerson Russell R. , Buchwitz Michael , Reuter Maximilian , Bovensmann Heinrich
Published: September 2014

In the past decade, there has been a massive growth in the horizontal drilling and hydraulic fracturing of shale gas and tight oil reservoirs to exploit formerly inaccessible or unprofitable energy resources in rock formations with low permeability. In North America, these unconventional domestic sources of natural gas and oil provide an opportunity to achieve energy self‐sufficiency and to reduce greenhouse gas emissions when displacing coal as a source of energy in power plants. However, fugitive methane emissions in the production process may counter the benefit over coal with respect to climate change and therefore need to be well quantified. Here we demonstrate that positive methane anomalies associated with the oil and gas industries can be detected from space and that corresponding regional emissions can be constrained using satellite observations. On the basis of a mass‐balance approach, we estimate that methane emissions for two of the fastest growing production regions in the United States, the Bakken and Eagle Ford formations, have increased by 990 ± 650 ktCH4 yr−1 and 530 ± 330 ktCH4 yr−1 between the periods 2006–2008 and 2009–2011. Relative to the respective increases in oil and gas production, these emission estimates correspond to leakages of 10.1% ± 7.3% and 9.1% ± 6.2% in terms of energy content, calling immediate climate benefit into question and indicating that current inventories likely underestimate the fugitive emissions from Bakken and Eagle Ford.
Microphysical, radiative, and dynamical impacts of thin cirrus clouds on humidity in the tropical tropopause layer and lower stratosphere
Authors: Dinh Tra , Fueglistaler Stephan
Published: September 2014

Cloud‐resolving numerical simulations are carried out to study how in situ formed cirrus affect the humidity in the tropical tropopause layer and lower stratosphere. Cloud‐induced impacts on the specific humidity are evaluated separately in terms of (i) the dehydration efficiency and (ii) the increase in the saturation mixing ratio associated with cloud radiatively induced temperature adjustment. The numerical results show that the dehydration efficiency of cirrus clouds, which is measured by the domain average relative humidity, varies within 100 ± 15% in all model configurations (with/without heterogeneous ice nucleation and with/without cloud radiative heating and cloud dynamics). A larger impact on the specific humidity comes from temperature increase (of a few kelvins) induced by cloud heating. The latter is found to scale approximately linearly with the domain average ice mass. Resolving the cloud radiatively induced circulations approximately doubles the domain average ice mass and associated cloud‐induced temperature change.
The effects of magnetic fields on photoelectron‐mediated spacecraft potential fluctuations
Authors: Wang X. , Malaspina D. M. , Hsu H.‐W. , Ergun R. E. , Horányi M.
Published: September 2014

Previously, we have experimentally studied photoelectron‐mediated spacecraft potential fluctuations associated with time‐dependent external electric fields. In this paper, we investigate the effects of magnetic fields on such spacecraft potential fluctuations. A magnetic field is created above the UV‐illuminated surface of a spacecraft model to alter the escape rate of photoelectrons. The packet of the observed potential oscillations becomes less positive with increasing magnetic field strength because more of the emitted photoelectrons are returned to the surface. As a result, the photoelectric charging time is increased, corresponding to a decrease in the response frequency of the photoemitting surface. The amplitude of the potential oscillations decreases when the response frequency becomes lower than the electric field oscillation frequency. A test particle simulation is validated with the laboratory experiments and applied to estimate the photoelectron escape rate from the Van Allen Probes spacecraft, showing that the photoelectron current is reduced by as much as 30% when magnetic field strength is 1200 nT. Based on our laboratory results and computer simulations, we discuss the effects of magnetic fields on the spacecraft potential fluctuations observed by the Van Allen Probes.
Linear separation of orthogonal merging component and viscous interactions in solar wind‐geospace coupling
Authors: Lopez R. E. , Bruntz R. , Pham K.
Published: September 2014

The general view is that the response of the magnetosphere‐ionosphere system to a complex, variable solar wind input will be a complicated and nonlinear function of that input. We investigate this question using a global MHD code to simulate the interaction and determine the responses of the system to isolated aspects of the solar wind input. We present evidence from the simulations that the solar wind‐geospace interaction can be linearly decomposed into component merging interactions for interplanetary magnetic field (IMF) By separate from Bz and a separate viscous interaction. One can run the global simulation (in our case, the Lyon‐Fedder‐Mobarry code) using just the solar wind plasma and Bz time series, do a second simulation using just the solar wind plasma and By time series, add the results of the two simulation outputs, then subtract the output from a simulation done with only the plasma input and no magnetic field, since the sum of the By and Bz runs has two viscous interactions (one for each run), and get an output that is very close to the result of a single run using the entire IMF merging field (By and Bz) along with the plasma time series. This demonstrates that the components of merging and viscous interactions between the solar wind and geospace are linearly separable to a very large degree.
Magnetic fields in the Venus ionosphere: Dependence on the IMF direction—Venus express observations
Authors: Dubinin E. , Fraenz M. , Zhang T. L. , Woch J. , Wei Y.
Published: September 2014

The structure of the magnetized ionosphere of Venus is investigated using the magnetometer and plasma (Analyzer of Space Plasmas and Energetic Atoms 4) data from the Venus Express spacecraft. Observations surveying the low‐altitude (h ≤ 250 km) ionosphere were made at solar zenith angles ≥ 75°. The magnetic field permeating the Venus ionosphere at solar minimum conditions increases at low altitudes and reaches a maximum at an altitude of ∼200 km. The orientation of the magnetic field in the peak is almost insensible to the magnetic field direction in the solar wind. For both sector polarities of the IMF, the magnetic field vector has a dominant dawn‐dusk component. The topology of the magnetic field also occurs different for different signs of the cross‐flow component of the IMF revealing either a sudden straightening with liberation of the magnetic field stresses or a closing into a loop. We discuss different mechanisms of the peak formation including local magnetization, a weak intrinsic planetary field, a dipole field induced by eddy currents, a remnant origin, or giant flux ropes. All of them fail to explain most of the observed features. We suggest that a decoupling of ion and electron motion at low altitudes due to ion‐neutral collisions results in currents which produce different field configurations depending on the IMF orientation.
The Comprehensive Inner Magnetosphere‐Ionosphere Model
Authors: Fok M.‐C. , Buzulukova N. Y. , Chen S.‐H. , Glocer A. , Nagai T. , Valek P. , Perez J. D.
Published: September 2014

Simulation studies of the Earth's radiation belts and ring current are very useful in understanding the acceleration, transport, and loss of energetic particles. Recently, the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model were merged to form a Comprehensive Inner Magnetosphere‐Ionosphere (CIMI) model. CIMI solves for many essential quantities in the inner magnetosphere, including ion and electron distributions in the ring current and radiation belts, plasmaspheric density, Region 2 currents, convection potential, and precipitation in the ionosphere. It incorporates whistler mode chorus and hiss wave diffusion of energetic electrons in energy, pitch angle, and cross terms. CIMI thus represents a comprehensive model that considers the effects of the ring current and plasmasphere on the radiation belts. We have performed a CIMI simulation for the storm on 5–9 April 2010 and then compared our results with data from the Two Wide‐angle Imaging Neutral‐atom Spectrometers and Akebono satellites. We identify the dominant energization and loss processes for the ring current and radiation belts. We find that the interactions with the whistler mode chorus waves are the main cause of the flux increase of MeV electrons during the recovery phase of this particular storm. When a self‐consistent electric field from the CRCM is used, the enhancement of MeV electrons is higher than when an empirical convection model is applied. We also demonstrate how CIMI can be a powerful tool for analyzing and interpreting data from the new Van Allen Probes mission.
Nonlinear evolution of the temperature gradient instability in the midlatitude ionosphere
Authors: Eltrass A. , Scales W. A.
Published: September 2014

The midlatitude Super Dual Auroral Radar Network radars frequently observe quiet time decameter‐scale irregularities in the nightside subauroral ionosphere. Since opposed temperature and density gradients are a persistent feature in the vicinity of the ionospheric projection of the plasmapause, the temperature gradient instability (TGI) is proposed to explain the observed irregularities. In this paper, modeling of the TGI is extended into the kinetic regime appropriate for HF radar frequencies and analyzed as the cause of these irregularities. The nonlinear evolution of the TGI is investigated utilizing gyrokinetic particle‐in‐cell simulation techniques with Monte Carlo collisions for the first time. The purpose of this investigation is to identify the mechanism responsible for the nonlinear saturation as well as the associated anomalous transport. It is found that the saturation amplitude level and the associated diffusion are greatly enhanced as a result of electron collisions. The simulation results indicate that the nonlinear E×Bconvection (trapping) of the electrons is the dominant TGI saturation mechanism. The spatial power spectra of the electrostatic potential and density fluctuations associated with the TGI are also computed, and the results show wave cascading of TGI from kilometer scales into the decameter‐scale regime of the radar observations. This implies that the E region may be responsible for shorting out the F region TGI electric fields before and around sunset. This also suggests that the observed midlatitude decameter‐scale ionospheric irregularities may be produced directly by the TGI or by turbulent cascade from primary longer‐wavelength irregularity structures produced from this instability.
Comparison of interplanetary CME arrival times and solar wind parameters based on the WSA‐ENLIL model with three cone types and observations
Authors: Jang Soojeong , Moon Y.‐J. , Lee Jae‐Ok , Na Hyeonock
Published: September 2014

We have made a comparison between coronal mass ejection (CME)‐associated shock propagations based on the Wang‐Sheeley‐Arge (WSA)‐ENLIL model using three cone types and in situ observations. For this we use 28 full‐halo CMEs, whose cone parameters are determined and their corresponding interplanetary shocks were observed at the Earth, from 2001 to 2002. We consider three different cone types (an asymmetric cone model, an ice cream cone model, and an elliptical cone model) to determine 3‐D CME cone parameters (radial velocity, angular width, and source location), which are the input values of the WSA‐ENLIL model. The mean absolute error of the CME‐associated shock travel times for the WSA‐ENLIL model using the ice‐cream cone model is 9.9 h, which is about 1 h smaller than those of the other models. We compare the peak values and profiles of solar wind parameters (speed and density) with in situ observations. We find that the root‐mean‐square errors of solar wind peak speed and density for the ice cream and asymmetric cone model are about 190 km/s and 24/cm3, respectively. We estimate the cross correlations between the models and observations within the time lag of ± 2 days from the shock travel time. The correlation coefficients between the solar wind speeds from the WSA‐ENLIL model using three cone types and in situ observations are approximately 0.7, which is larger than those of solar wind density (cc ∼0.6). Our preliminary investigations show that the ice cream cone model seems to be better than the other cone models in terms of the input parameters of the WSA‐ENLIL model.
Testing models of sub‐slab anisotropy using a global compilation of source‐side shear wave splitting data
Authors: Lynner Colton , Long Maureen D.
Published: September 2014

Recently, a number of source‐side shear wave splitting measurements that directly constrain anisotropy in the upper mantle beneath subducting slabs have been published. Such measurements have yielded an observational foundation on which to base our understanding of the dynamics of the sub‐slab mantle. Here we compile measurements from recent studies of source‐side splitting beneath slabs that employ identical measurement and processing techniques. We use this compilation to test the predictions of a number of recently proposed conceptual models for the dynamics of the sub‐slab mantle, including those that invoke three‐dimensional return flow beneath slabs, strong radial anisotropy in suboceanic asthenosphere that is entrained via subduction, and a model based on the correlation between sub‐slab splitting behavior and the age of the subducting lithosphere. We find that a model in which fast splitting directions are determined by slab age matches the observations better than either the 3‐D return flow or radial anisotropic models. Based on this observation, we propose that the sub‐slab mantle is characterized by two distinct anisotropic and mantle flow regimes. Beneath younger lithosphere (<95 Ma), we propose that the sub‐slab mantle is characterized by 2‐D entrained flow resulting in an entrained mantle layer. Beneath older lithosphere (>95 Ma), the entrained layer is thin and effectively serves as decoupling layer; the dynamics of the sub‐slab region beneath old lithosphere is therefore dominated by three‐dimensional return flow. This variation in the amount of mechanical coupling may be facilitated by the onset of small‐scale convection beneath older lithosphere.
Thermal equation of state of majoritic knorringite and its significance for continental upper mantle
Authors: Dymshits Anna M. , Litasov Konstantin D. , Sharygin Igor S. , Shatskiy Anton , Ohtani Eiji , Suzuki Akio , Funakoshi Kenichi
Published: September 2014

The P‐V‐T equation of state (EoS) for majoritic knorringite Mg3.19Cr1.60Si3.19O12 at pressures to 17 GPa and temperatures to 1673 K was obtained from in situ X‐ray diffraction experiments using a Kawai‐type multi‐anvil apparatus. Fitting of the room‐temperature P–V data to a third‐order Birch‐Murnaghan EoS yielded an isothermal bulk modulus, K0,300 = 154 (4) GPa, and a pressure derivative, K′0,300 = 5.4 (1.2). When fitting a high‐temperature Birch‐Murnaghan EoS using all of the P‐V‐T data at a fixed V0 = 1549.08 Å3, we find that K0,300 = 157 (2) GPa, K′0,T = 4.5 (6), (∂K0,T/∂T)P = −0.019 (4) (GPa K−1), a = 3.00 (14) × 10−5 K−1, and b = 0.65 (24) × 10−8 K−2, where α = a + bT is the volumetric thermal expansion coefficient. Fitting the Mie‐Grüneisen‐Debye EoS with the present data with a Debye temperature fixed at θ0 = 731 K yielded a Grüneisen parameter, γ0 = 1.34 at q = 1.0 (fixed). The thermoelastic parameters of pure knorringite were estimated and were compared with the previous data on other garnet compositions. The presence of Cr2O3 in pyrope garnets in the upper mantle decreases P‐ and S‐velocities by 1.6% and the density increases by 1.7% (for 20 mol.% knorringite end member) compared to pure pyrope. The results show the importance of accounting knorringite end‐member for accurate estimation of mantle garnet acoustic velocities.
Net community production and export from Seaglider measurements in the North Atlantic after the spring bloom
Authors: Alkire Matthew B. , Lee Craig , D'Asaro Eric , Perry Mary Jane , Briggs Nathan , Cetinić Ivona , Gray Amanda
Published: September 2014

Mean rates of net community production (NCP) and particulate organic carbon (POC) export were estimated from sensor measurements of dissolved oxygen (O2), chlorophyll fluorescence (chl F), and particulate backscatter (bbp700) collected from three Seagliders that surveyed a 20 × 20 km area in the North Atlantic subsequent to a large diatom bloom. Since the Seagliders sampled geographically fixed patterns, care was taken in the calculation of all terms applicable to the Eulerian reference frame, including local rate of change, vertical mixing, air‐sea exchange, and horizontal advection. Although similar studies of NCP in the open ocean have generally assumed advection to be insignificant, we have found that this term cannot be ignored when dealing with temporal scales of ≤1 month and/or spatial scales ≤20 km. The overlapping sampling pattern of the Seagliders was sufficiently rapid such that 4–5 day time scales observed in the O2 and POC data were adequately resolved and variations were not a consequence of aliasing spatial variability. During the study period, ratios of chlorophyll fluorescence‐to‐particulate backscatter (chl:bbp700) were lower than values encountered during the spring diatom bloom, suggesting the phytoplankton community was predominantly composed of smaller cells (picoplankton and nanoplankton) and/or coccolithophorids. Coupled budgets of oxygen and POC indicated a net community production of 1.0 mol C m−2 and carbon export of 0.6 mol C m−2, respectively, over a period of 23 days. Thus, the production and export of carbon that occurred over the month‐long experiment period was comparable to that encountered during the spring bloom.
Evidence of mixing between polluted convective outflow and stratospheric air in the upper troposphere during DC3
Authors: Schroeder Jason R. , Pan Laura L. , Ryerson Tom , Diskin Glenn , Hair Johnathan , Meinardi Simone , Simpson Isobel , Barletta Barbara , Blake Nicola , Blake Donald R.
Published: September 2014

Aircraft measurements, including non‐methane hydrocarbons (NMHCs), long‐lived halocarbons, carbon monoxide (CO), and ozone (O3) collected on board the NASA DC‐8 during the Deep Convection, Clouds, and Chemistry (DC3) field campaign (May – June 2012), were used to investigate interactions and mixing between stratospheric intrusions and polluted air masses. Stratospherically influenced air masses were detected using a suite of long‐lived halocarbons, including chlorofluorocarbons (CFCs) and HCFCs, as a tracer for stratospheric air. A large number of stratospherically influenced samples were found to have reduced levels of O3 and elevated levels of CO (both relative to background stratospheric air), indicative of mixing with anthropogenically influenced air. Using n‐butane and propane as further tracers of anthropogenically influenced air, we show that this type of mixing was present both at low altitudes and in the upper troposphere (UT). At low altitudes, this mixing resulted in O3 enhancements consistent with those reported at surface sites during deep stratospheric intrusions, while in the UT, two case studies were performed to identify the process by which this mixing occurs. In the first case study, stratospheric air was found to be mixed with aged outflow from a convective storm, while in the second case study, stratospheric air was found to have mixed with outflow from an active storm occurring in the vicinity of a stratospheric intrusion. From these analyses, we conclude that deep convective events may facilitate the mixing between stratospheric air and polluted boundary layer air in the UT. Throughout the entire DC3 study region, this mixing was found to be prevalent: 72% of all samples that involve stratosphere‐troposphere mixing show influence of polluted air. Applying a simple chemical kinetics analysis to these data, we show that during DC3, the instantaneous production of hydroxyl radical (OH) in these mixed stratospheric‐polluted air masses was 11 ± 8 times higher than that of stratospheric air, and 4.2 ± 1.8 times higher than that of background upper tropospheric air.
Hybrid White Light Emitting Diode Based on Silicon Nanocrystals
Authors: Ghosh Batu , Masuda Yoshitake , Wakayama Yutaka , Imanaka Yasutaka , Inoue Jun‐ichi , Hashi Kenjiro , Deguchi Kenzo , Yamada Hideto , Sakka Yoshio , Ohki Shinobu , Shimizu Tadashi , Shirahata Naoto
Published: September 2014

A novel design of white light emitting diodes (WLEDs) emerges to meet the growing global demand for resource sustainability while preserving health and environment. To achieve this goal, a facile method is developed for the chemical synthesis of a luminescent silicon nanocrystal (ncSi) with a large Stokes shift between absorption and emission. The WLED is prepared by a simple spin‐coating method, and contains a hybrid‐bilayer of the ncSi and luminescent polymer in its device active region. Interestingly, a well‐controlled ultrathin ncSi layer on the polymer makes possible to recombine electrons and holes in both layers, respectively. Combining red and blue‐green lights, emitted from the ncSi and the polymer layers, respectively, produces the emission of white electroluminescence. Herein, a hybrid‐WLED with a sufficiently low turn‐on voltage (3.5 V), produced by taking advantages of the large Stokes shift inherent in ncSi, is demonstrated.