bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence Based Solving Approach in Diagnosis of Primary Hyperparathyroidism with Oral Manifestations: Report of Three Unusual Cases
Authors: Bindal Ruchi , Kumar Ajay , Singh Harkanwal Preet , Bansal Sanjiv Kumar , Sharma Aadya
Published: October 2013

Primary hyperparathyroidism is a common condition that affects 0.3% of the general population in which excessive production of PTH is there. With changing trends it is diagnosed early and asymptomatically with the improvements in routine biochemical tests and radiological procedures. The late bony complications of the disease have therefore started to decline rapidly. The mandible is the predominantly affected site in the maxillofacial area. Maxillary involvement is rare. Here, we reported series of three cases of 30-40-year-old women with osteolytic lesions and bone resorption in maxilla or mandible. Two of presented cases demonstrated evidence of lesions in both mandible and maxilla which is a very rare event. A thorough diagnostic work-up emphasizing on biochemical and radiographic investigations were discussed. We highlighted the role of endocrinologist, oral and maxillofacial surgeons, general practitioner dentists, and radiologists in diagnosing and managing such patients.
Isolated Plexiform Neurofibroma of the Tongue
Authors: Sharma Abhishek , Sengupta Parama , Das Anjan KR
Published: October 2013

Neurofibromas (NF) are benign tumors of neural origin, of which roughly 90% appear as solitary lesions. They are classified into cutaneous, subcutaneous, and plexiform subtypes. Plexiform neurofibromas are the least common variant and usually are pathognomonic for NF I. Here, we present a very rare case of isolated plexiform neurofibroma with a painless enlarging mass of the tongue of an 11-year-old girl. This rare benign tumor has the potential for malignant transformation, and the diagnosis was difficult owing to the patient's age and to the insidious clinical presentation. The present case is a diffuse isolated plexiform neurofibroma of the tongue that was not associated with neurofibromatosis that was treated with intraoral surgery.
Pattern of salivary gland tumors in Manipur, India: A 10 year study
Authors: Laishram Rajesh Singh , K. Arun Kumar , Pukhrambam Gayatri Devi , Laishram Sharmila , Debnath Kaushik
Published: October 2013

Background: Salivary gland lesions, especially the neoplastic lesions constitute a highly heterogeneous histopathologic group. Several studies have reported a significant difference in the global distribution of salivary gland tumors, but no formal study has been carried out in this part of the globe. Objectives: To document the pattern of various salivary gland tumors in Manipur, a state in North Eastern India. Materials and Methods: This is a 10 years (2002-2011) retrospective study of all salivary gland specimens received at our referral teaching hospital in Manipur, India. All the histopathology slides of salivary gland specimens during the study period were reviewed and clinical details were obtained from the archives. Restaining of slides and fresh sections of tissue blocks were performed whenever required. Data thus collected were analyzed. Results: A total of 104 cases of salivary gland lesions were studied during the study period. Age ranged from 5 years to 78 years with an overall slight female preponderance (M:F = 1:1.08). Parotid (56.65%) was the commonest gland involved followed by submandibular gland (31.73%). Neoplastic lesions comprised of 78 (75%) cases and non-neoplastic lesions constituted 25% (26 cases). Among the neoplastic lesions, benign lesions (53.85%) predominated over malignant lesions (21.15%). Pleomorphic adenoma was the commonest benign neoplastic lesion and mucoepidermoid carcinoma was the commonest malignant tumor. Chronic sialadenitis was the predominant lesion in the non-neoplastic group. Conclusion: The principal site for salivary gland tumors was the parotid gland and pleomorphic adenoma outnumbered all the other tumors. Females are more affected in the malignant group.
Assessment of cancer care in Indian elderly cancer patients: A single center study
Authors: Sarkar Anindya , Shahi UP
Published: October 2013

Background and purpose: This prospective study aimed to assess the profiles of elderly cancer patient to optimize cancer care in Indian setup. The profiles have been compared with that of younger patients in terms of epidemiological, clinical data, co‑morbidity, treatment, toxicity, clinical outcome, and survival pattern. Materials and Methods: The study comprised cancer patients attending radiotherapy outdoor (November 2005 to June 2006). There were 104 patients of age ≥60 years (elderly group) and 121 patients of 45-59 years (younger group). Results: Elderly group had median age 65 years (60-88 years) with M:F = 1:1. The younger group had median age 50 years (45-59 years) with M:F = 1:2. Elderly had higher proportion of gastrointestinal and genito‑urinary tract malignancies. Younger group had higher proportion of breast, lymphoma, and brain tumor. 13% had co‑morbidity, 50% received treatment, 27% were treated with radiotherapy with or without surgery, and two‑third of these cases belong to elderly group. Majority tolerated treatment well. 10% had significant grade of toxicity. 57% of elderly patients did not accept and one‑fourth of all cases did not complete the prescribed treatment. 88% cases were responders of which 70% showed complete response. There were no differences between two groups. At 12 months 35% of treated patients came for follow‑up. At first 12 months, 60-70% were alive without disease. Conclusion: There were differences between two groups in terms of performance status, treatment acceptance, and treatment modality prescribed. Elderly patients deserve same opportunity as younger patients for treatment and survival options from the oncologist.
Elizabethkingia meningoseptica bacteremia in immunocompromised hosts: The first case series from India
Authors: Ghafur Abdul , Vidyalakshmi P. R. , Priyadarshini K. , Easow Jose M. , Raj Revathi , Raja T.
Published: October 2013

Background: Although Elizabethkingia meningoseptica (Chryseobacterium meningosepticum) infections in immunocompromised hosts have been recognised, clinical data detailing these infections remain limited, especially from India. Antimicrobial susceptibility data on E. meningoseptica remain very limited, with no established breakpoints by Clinical and Laboratory Standards Institute (CLSI). The organism is usually multidrug resistant to antibiotics usually prescribed for treating Gram-negative bacterial infections, a serious challenge to the patient and the treating clinicians. Materials and Methods: The analysis was done in a tertiary care oncology and stem cell transplant center. Susceptibility testing and identification of E. meningoseptica was done using Vitek auto analyzer. Records of immunocompromised patients with E. meningoseptica bacteremia were analysed from January 2009 to March 2012. Results: A total of 29 E. meningoseptica bacteremia cases were documented between 2009 and 2012. Eleven patients were immunocompromised. Three were post stem cell transplant and one was post cord blood transplant. The mean age of the patients was 48.4 years. Mean Charlson’s comorbidity index was 5.7. Four had solid organ malignancies, five had hematological malignancies, and two had lymphoreticular malignancy. Eight patients had received chemotherapy. Mean Apache II score was 18. Mean Pitts score for bacteremia was 4.7. Two were neutropenic (one post SCT, one MDS post chemo) with a mean white blood cell (WBC) count of 450/mm3. Ten had a line at the time of bacteremia. Mean duration of the line prior to bacteremia was 8 days. Eight had line-related bacteremia. Three had pneumonia with secondary bacteremia. All received combination therapy with two or more antibiotics which included cotrimoxazole, rifampicin, piperacillin–tazobactam, tigecycline, or cefepime–tazobactam. All the isolates showed in vitro resistance to ciprofloxacin. Five patients died, but a multivariate analysis was not done to calculate the attributable mortality. Conclusion: In our study, central line was the commonest risk factor for E. meningosepticum bacteremia, although a multivariate analysis was not done. There has not been much of a change in the susceptibility pattern of these organisms over 3 years, with good susceptibility to piperacillin–tazobactam and cotrimoxazole. Even though uncommon, E. meningoseptica is an important pathogen, especially in immunocompromised hosts with indwelling devices.
Be a true listener, rather than a good conversationalist
Authors: Mehdi Itrat , Al-Bahrani Bassim Jaffar
Published: October 2013

Oncology patient care is an ever evolving field both as a science and a clinical art. We evaluate, diagnose, and treat cancer patients daily. We break the bad and the good news to them. We are the hope on which their life and dreams hang on. We, as practitioners, have to assess each patient as an intelligent observer. We have to devise our strategy to break heartbreaking news to them in a tailored and personalized fashion according to the physical, psychological, emotional, and social status of the patient. The process has to be gentle, perceptive, pragmatic, yet truthful. These need to be reasonably good observational, listening, comprehending, and delivering potentials; which are sharpened by experience and skills.
Prognostic factors for mortality with fungal blood stream infections in patients with hematological and non-hematological malignancies
Authors: Salih Zena , Cavet Jim , Dennis Mike , Somervaille Tim , Bloor Adrian , Kulkarni Samar
Published: October 2013

Background: This single center retrospective analysis was undertaken to identify the incidence, clinical impact, and prognostic factors for mortality associated with fungal blood stream infections (BSI) in cancer patients. Materials and Methods: One hundred and twenty four patients had 169 episodes of fungal BSI. Incidence has not changed over a 10 year period but non albicans candida species are the predominant fungal isolates. Mortality with fungal BSI was significantly higher than that with other microbial agents. Risk of mortality was associated with renal dysfunction and Candida albicans as the isolate. Type of chemotherapy, patient characteristics, and neutrophil count did not influence the mortality following fungal BSI. Conclusion: Fungal BSI is rare and the incidence has not changed in this hospital. Mortality associated with fungal BSI is high. Risk score at the time of developing fungal BSI has prognostic potential to identify patients with higher risk of mortality associated with fungal BSI.
Sphincter-saving surgeries for rectal cancer: A single center study from Kashmir
Authors: Mir Shabeer Ahmed , Chowdri Nisar A. , Parray Fazl Q. , Mir Parvez Ahmed , Bashir Yasir , Nafae Muntakhab
Published: October 2013

Summary and Background Data: The goals in the treatment of rectal cancer are cure, local control, and preservation of sphincter, bladder and sexual function. Surgical resection using sharp mesorectal dissection is important for achieving these goals. Objectives: The current treatment of choice for carcinoma rectum is sphincter saving procedures, which have practically replaced the previously done abdominoperineal resection. We performed a study in our institute to evaluate the surgical outcome and complications of rectal cancer. Materials and Methods: This prospectivestudy included 117 patients, treated for primary rectal cancer by low anterior resection (LAR) from May 2007 to December 2010. All patients underwent standard total mesorectal excision (TME) followed by restoration of continuity. Results: The peri-operative mortality rate was 2.5% (3/117). Post-operative complications occurred in 32% of the patients. After a median follow up of 42 months, local recurrences developed in 6 (5%) patients and distant metastasis in 5 (4.2%). The survival rate was 93%. Conclusion: The concept of total mesorectal excision (TME), advances in stapling technology and neoadjuvant therapy have made it possible to preserve the anal sphincter in most of the patients. Rectal cancer needs to be managed especially in a specialized unit for better results.
Cervical Lymph Node Sarcoidosis Mimicking a Parathyroid Adenoma: A Clinical Case
Authors: Calò Pietro Giorgio , Pisano Giuseppe , Tatti Alberto , Loi Giulia , Furcas Silvia , Nicolosi Angelo
Published: October 2013

We report a case of cervical lymph node sarcoidosis misdiagnosed as parathyroid adenoma. This is the second case described in the literature in which lymph node sarcoidosis was misdiagnosed as parathyroid adenoma on Tc-99m sestamibi (MIBI) scan, the first case localized in the neck. A 64-year-old woman presented with a hypercalcemia. Neck ultrasonography revealed a paratracheal hypoechoic mass of 15 mm with peripheral vascularization. MIBI scan and SPECT/CT identified a MIBI-positive area corresponding to the nodule detected by ultrasonography suggestive for a lower right parathyroid adenoma. A mass interpreted as the lower parathyroid was excised associated to a total thyroidectomy. Pathologic examination revealed a granulomatous lymph node consistent with active sarcoidosis. Sarcoidosis should be suspected as a cause of unexplained hypercalcemia and the differential diagnosis of hypercalcemia, even in presence of MIBI uptake, must include sarcoidosis localized in an isolated cervical lymph node.
Leiomyosarcoma of the Splenic Vein
Authors: Aguilar Cristian , Socola Francisco , Donet Jean A. , Gallastegui Nicolas , Hernandez Gabriel A.
Published: October 2013

Leiomyosarcomas arising from the wall of blood vessels are rare and aggressive neoplasm. We report a case of a previously healthy 66-year-old woman who presented with intermittent abdominal pain, progressive constipation, and weight loss. Abdominal computed tomography showed a 12 cm solid heterogeneous tumor in the tail of the pancreas. The patient subsequently underwent surgical resection of the pancreatic mass. Surprisingly, histological and immunohistochemical analyses revealed leiomyosarcoma arising from the smooth muscle of the splenic vein. After surgery, she received adjuvant chemotherapy. One year later, there was no evidence of local recurrence. In this paper, we discuss the available information about leiomyosarcomas of splenic vein and its management.
Tensor complexes: multilinear free resolutions constructed from higher tensors
Authors: Berkesch Zamaere Christine , Erman Daniel , Kummini Manoj , Sam Steven V
Published: October 2013

The most fundamental complexes of free modules over a commutative ring are the Koszul complex, which is constructed from a vector (i.e., a

1

-tensor), and the Eagon–Northcott and Buchsbaum–Rim complexes, which are constructed from a matrix (i.e., a

2

-tensor). The subject of this paper is a multilinear analogue of these complexes, which we construct from an arbitrary higher tensor. Our construction provides detailed new examples of minimal free resolutions, as well as a unifying view on a wide variety of complexes including: the Eagon–Northcott, Buchsbaum–Rim and similar complexes, the Eisenbud–Schreyer pure resolutions, and the complexes used by Gelfand–Kapranov–Zelevinsky and Weyman to compute hyperdeterminants. In addition, we provide applications to the study of pure resolutions and Boij–Söderberg theory, including the construction of infinitely many new families of pure resolutions, and the first explicit description of the differentials of the Eisenbud–Schreyer pure resolutions.
A support theorem for Hilbert schemes of planar curves
Authors: Migliorini Luca , Shende Vivek
Published: October 2013

Consider a family of integral complex locally planar curves whose relative Hilbert scheme of points is smooth. The decomposition theorem of Beilinson, Bernstein, and Deligne asserts that the pushforward of the constant sheaf on the relative Hilbert scheme splits as a direct sum of shifted semisimple perverse sheaves. We will show that no summand is supported in positive codimension. It follows that the perverse filtration on the cohomology of the compactified Jacobian of an integral plane curve encodes the cohomology of {\em all} Hilbert schemes of points on the curve. Globally, it follows that a family of such curves with smooth relative compactified Jacobian ("moduli space of D-branes'') in an irreducible curve class on a Calabi-Yau threefold will contribute equally to the BPS invariants in the formulation of Pandharipande and Thomas, and in the formulation of Hosono, Saito, and Takahashi.
The nonlinear future stability of the FLRW family of solutions to the irrotational Euler–Einstein system with a positive cosmological constant
Authors: Rodnianski Igor , Speck Jared
Published: October 2013

In this article, we study small perturbations of the family of Friedmann-Lemaître-Robertson-Walker cosmological background solutions to the coupled Euler-Einstein system with a positive cosmological constant in

1 + 3

spacetime dimensions. The background solutions model an initially uniform quiet fluid of positive energy density evolving in a spacetime undergoing exponentially accelerated expansion. Our nonlinear analysis shows that under the equation of state

p = c^2 \rho, 0 < c^2 < 1/3

, the background metric + fluid solutions are globally future-stable under small irrotational perturbations of their initial data. In particular, we prove that the perturbed spacetime solutions, which have the topological structure

[0,\infty) X T^3

, are future causally geodesically complete. Our analysis is based on a combination of energy estimates and pointwise decay estimates for quasilinear wave equations featuring dissipative inhomogeneous terms. Our main new contribution is showing that when

0 < c^2 < 1/3

, exponential spacetime expansion is strong enough to suppress the formation of fluid shocks. This contrasts against a well-known result of Christodoulou, who showed that in Minkowski spacetime, the corresponding constant-state irrotational fluid solutions are unstable.
Primary Prophylaxis of Disseminated Histoplasmosis in HIV Patients in French Guiana: Arguments for Cost Effectiveness
Authors: Nacher Mathieu , Adenis Antoine , Basurko Celia , Vantilcke Vincent , Blanchet Denis , Aznar Christine , Carme Bernard , Couppié Pierre
Published: October 2013

Histoplasmosis is the first cause of acquired immunodeficiency syndrome (AIDS) and AIDS-related deaths in French Guiana. Cohort data were used to determine whether primary prophylaxis with 100 mg itraconazole for patients with CD4 counts < 150/mm3 was cost-effective with different scenarios. For a scenario where 12% of patients died, 60% were aware of their human immunodeficiency virus (HIV) infection and adherence was only 50%, primary prophylaxis would prevent 1 death and 9 cases of histoplasmosis for a cost of 36,792 Euros per averted death, 1,533 per life-year saved, 4,415 Euros per averted case, when only counting the costs of itraconazole prophylaxis. Taking into account the total costs of hospitalization showed that primary prophylaxis would allow a savings of 185,178 Euros per year. Even in a scenario of low adherence, primary prophylaxis would be cost-effective in French Guiana, and presumably in the rest of the Guianas and the Amazon.
Development of an Novel Non-Eccentric Rotational Engine “Ishino Engine”(Fundamental Configuration and Characteristics)
Authors: Ishino Yojiro , Teshima Keisuke , Fujii Hiroyuki , Yamamoto Yusaku , Saiki Yu
Published: October 2013

A novel rotational internal combustion engine is invented and investigated. In this engine, no eccentric rotational component is used, resulting in vibration-free operation. For this characteristics, this engine will be suitable for usage in silent environment, e.g. co-generation house plant, handy-usage and so on. The engine mainly consists of a rotor casing and two types of rotor; cycloid rotor and trochoid rotor. The shape of the cycloid rotor is characterized by epicycloid surface and lobes, and the trochoid rotor also superior-epitrochoid surface and concaves. As mentioned above, fundamental process of intake, compression, ignition, expansion and exhaust for working gas is automatically performed by the constant speed rotation of both of rotors. In this paper, first, the typical configuration including two designing procedure of the rotors are described in detail. Next the cyclic behavior of the working process is explained. Furthermore the design drawing of the prototype engine is given. The time variations of chamber volume and pressure of typical configuration of the prototype engine are estimated. Also the comparison in engine compactness and compression ratio is made for another types of engine.
Evaluation of Value Proposition and Interactive Features for Motorcycles with Electronic Fuel Injection for Indian Market
Authors: R Pradeep , Shetty Ajay , M Prabhu Panduranga
Published: October 2013

Growth and mobility expectation in India has increased competition in the Indian two wheeler industry. Value proposition targeting improved performance, fuel economy, user-friendly features are being seen as key differentiators. The expected introduction of EFI (Electronic Fuel Injection) leads to additional system cost which needs to be justified from tangible end-customer benefits. The previous SAE papers [1] [2] attempted to provide an insight into the carbureted engine vs. fuel injection systems from fuel efficiency, combustion quality perspective and also enumerated the benefit of fuel economy to end user.

To increase the benefit to the end customers, the authors propose to provide insight into innovative system concepts with interactive features. The evaluation targets the commuter segment where the implementation and acceptance potential is high. The results thus derived on the motorcycle under consideration are promising and has high potential to meet the needs of the end user.

Throttle enabled start, start-stop, bypass less throttle body, operating mode selection, “battery dead” ignition are a few of the features which can be implemented for a EFI bike increasing the value proposition and reducing the overall system cost for the OEM.
Seasonal and diel patterns in sedimentary flux of krill fecal pellets recorded by an echo sounder
Authors: Røstad Anders , Kaartvedt Stein
Published: October 2013

We used a moored upward‐facing 200 kHz echo sounder to address sedimentation of fecal pellets (FPs) from dielly migrating Meganyctiphanes norvegica. The echo sounder was located on the bottom at 150 m depth in the Oslofjord, Norway, and was cabled to shore for continuous measurements during winter and spring. Records of sinking pellets were for the first time observed with an echo sounder. Seasonal patterns of sedimentation of krill FPs were strongly correlated with data from continuous measurement of fluorescence, which illustrate the development of the spring bloom. Sedimenting particles were first observed as fluorescence values started to increase at the end of February and continued to increase until the bloom suddenly culminated at the end of March. This collapse of the bloom was detected on the echo sounder as a pulse of slowly sinking acoustic targets over a 2 d period. Prior to this event, there was a strong diel pattern in sedimentation, which correlated, with some time lag, with the diel migration of krill foraging at night near the surface. Pellet average sinking speeds ranged between 423 m d−1 and 804 m d−1, with a strong relation to pellet target strength, which is an acoustic proxy for size. This novel approach shows that echo sounders may be a valuable tool in studies of vertical pellet flux and, thereby, carbon flux, providing temporal resolution and direct observation of the sedimentation process, which are not obtained from standard methods.
Video-Based Analysis of Bodily Startle and Subsequent Emotional Facial Expression in Posttraumatic Stress Disorder
Authors: Blechert Jens , Michael Tanja , Wilhelm Frank H.
Published: October 2013

Exaggerated startle is a core hyperarousal symptom of Posttraumatic Stress Disorder (PTSD). Observational studies on the characteristics of this response are strikingly lacking. Previous research has demonstrated that detailed video analysis of facial and bodily responses to startling stimuli enables the differentiation of an initial, primarily reflexive response and a secondary, primary emotional response. We exposed PTSD patients (n = 34) and trauma-exposed but healthy participants (TE group, n = 26) to startling electric stimuli while acquiring observational behavioral, psychophysiological, and experiential measures. Videographic results indicate that PTSD patients' initial bodily startle response was stronger than in the TE group, and their secondary facial expression was more negatively valenced, largely due to elevated anger expression. Videographic assessment of primary and secondary startle responses provides a new window into reflexive and emotional functioning of PTSD and may therefore complement existing startle measures. PTSD treatments should address bodily startle, negative symptom appraisals, and anger more specifically.
Chemical evolution of organic aerosol in Los Angeles during the CalNex 2010 study
Authors: Holzinger R. , Goldstein A. H. , Hayes P. L. , Jimenez J. L. , Timkovsky J.
Published: October 2013

Abstract. During the CalNex study (15 May to 16 June 2010) a large suite of instruments was operated at the Los Angeles area ground supersite to characterize the sources and atmospheric processing of atmospheric pollution. The thermal-desorption proton-transfer-reaction mass-spectrometer (TD-PTR-MS) was deployed to an urban area for the first time and detected 691 organic ions in aerosol samples, the mean total concentration of which was estimated as 3.3 μg m−3. Based on comparison to total organic aerosol (OA) measurements, we estimate that approximately 50% of the OA mass at this site was directly measured by the TD-PTR-MS. Based on correlations with aerosol mass spectrometer (AMS) OA components, the ions were grouped to represent hydrocarbon-like OA (HOA), local OA (LOA), semi-volatile oxygenated OA (SV-OOA), and low volatility oxygenated OA (LV-OOA). Mass spectra and thermograms of the ion groups are mostly consistent with the assumed sources and/or photochemical origin of the OA components. The mass spectra of ions representing the primary components HOA and LOA included the highest m/z, consistent with their higher resistance to thermal decomposition, and they were volatilized at lower temperatures (~ 150 °C). Photochemical ageing weakens C-C bond strengths (also resulting in chemical fragmentation), and produces species of lower volatility (through the addition of functional groups). Accordingly the mass spectra of ions representing the oxidized OA components (SV-OOA, and LV-OOA) lack the highest masses and they are volatilized at higher temperatures (250–300 °C). Chemical parameters like mean carbon number (nC), mean carbon oxidation state (OSC), and the atomic ratios O / C and H / C of the ion groups are consistent with the expected sources and photochemical processing of the aerosol components. Our data suggest that chemical fragmentation gains importance over functionalization as photochemical age of OA increases. Surprisingly, the photochemical age of OA decreases during the daytime hours, demonstrating the importance of rapid production of new (photochemically young) SV-OOA during daytime. The PTR detects higher organic N concentrations than the AMS, the reasons for which are not well understood and cannot be explained by known artifacts related to PTR or the AMS. The median atomic N / C ratio (6.4%) of the ion group representing LV-OOA is a factor 2 higher than N / C of any other ion group. This suggests a multiphase chemical source involving ammonium ions is contributing to LV-OOA.
Fine particulate matter source apportionment using a hybrid chemical transport and receptor model approach
Authors: Hu Y. , Balachandran S. , Pachon J. E. , Baek J. , Ivey C. , Holmes H. , Odman M. T. , Mulholland J. A. , Russell A. G.
Published: October 2013

Abstract. A hybrid fine particulate matter (PM2.5) source apportionment approach based on a receptor-model (RM) species balance and species specific source impacts from a chemical transport model (CTM) equipped with a sensitivity analysis tool is developed to provide physically- and chemically-consistent relationships between source emissions and receptor impacts. This hybrid approach enhances RM results by providing initial estimates of source impacts from a much larger number of sources than are typically used in RMs, and provides source-receptor relationships for secondary species. Further, the method addresses issues of source collinearities, and accounts for emissions uncertainties. Hybrid method results also provide information on the resulting source impact uncertainties. We apply this hybrid approach to conduct PM2.5 source apportionment at Chemical Speciation Network (CSN) sites across the US. Ambient PM2.5 concentrations at these receptor sites were apportioned to 33 separate sources. Hybrid method results led to large changes of impacts from CTM estimates for sources such as dust, woodstove, and other biomass burning sources, but limited changes to others. The refinements reduced the differences between CTM-simulated and observed concentrations of individual PM2.5 species by over 98% when using a weighted least squared error minimization. The rankings of source impacts changed from the initial estimates, revealing that CTM-only results should be evaluated with observations. Assessment with RM results at six US locations showed that the hybrid results differ somewhat from commonly resolved sources. The hybrid method also resolved sources that typical RM methods do not capture without extra measurement information on unique tracers. The method can be readily applied to large domains and long (such as multi-annual) time periods to provide source impact estimates for management- and health-related studies.
Simulation of semi-explicit mechanisms of SOA formation from glyoxal in a 3-D model
Authors: Knote C. , Hodzic A. , Jimenez J. L. , Volkamer R. , Orlando J. J. , Baidar S. , Brioude J. , Fast J. , Gentner D. R. , Goldstein A. H. , Hayes P. L. , Knighton W. B. , Oetjen H. , Setyan A. , Stark H. , Thalman R. , Tyndall G. , Washenfelder R. , Waxman E. , Zhang Q.
Published: October 2013

Abstract. New pathways to form secondary organic aerosols (SOA) have been postulated recently. Glyoxal, the smallest dicarbonyl, is one of the proposed precursors. It has both anthropogenic and biogenic sources, and readily partitions into the aqueous-phase of cloud droplets and deliquesced aerosols where it undergoes both reversible and irreversible chemistry. In this work we extend the regional scale chemistry transport model WRF-Chem to include a detailed gas-phase chemistry of glyoxal formation as well as a state-of-the-science module describing its partitioning and reactions in the aqueous-phase of aerosols. A comparison of several proposed mechanisms is performed to quantify the relative importance of different formation pathways and their regional variability. The CARES/CalNex campaigns over California in summer 2010 are used as case studies to evaluate the model against observations. In all simulations the LA basin was found to be the hotspot for SOA formation from glyoxal, which contributes between 1% and 15% of the model SOA depending on the mechanism used. Our results indicate that a mechanism based only on a simple uptake coefficient, as frequently employed in global modeling studies, leads to higher SOA contributions from glyoxal compared to a more detailed description that considers aerosol phase state and chemical composition. In the more detailed simulations, surface uptake is found to be the main contributor to SOA mass compared to a volume process and reversible formation. We find that contribution of the latter is limited by the availability of glyoxal in aerosol water, which is in turn controlled by an increase in the Henry's law constant depending on salt concentrations ("salting-in"). A kinetic limitation in this increase prevents substantial partitioning of glyoxal into aerosol water at high salt concentrations. If this limitation is removed, volume pathways contribute >20% of glyoxal SOA mass, and the total mass formed (5.8% of total SOA in the LA basin) is about a third of the simple uptake coefficient formulation without consideration of aerosol phase state and composition. All these model formulations are based on very limited and recent field or laboratory data and we conclude that the current uncertainty on glyoxal SOA formation spans a factor of 10 in this domain and time period.
The genesis of Typhoon Nuri as observed during the Tropical Cyclone Structure 2008 (TCS-08) field experiment – Part 3: Dynamics of low-level spin-up during the genesis
Authors: Lussier L. L. , Montgomery M. T. , Bell M. M.
Published: October 2013

Abstract. Aircraft reconnaissance data collected during the Tropical Cyclone Structure 2008 field campaign are used to examine further kinematical, dynamical and thermodynamical aspects of the genesis of Typhoon Nuri. Data from the first two missions into the pre-Nuri disturbance document the transition from a tropical wave to a tropical depression. Dropwindsonde-derived tangential wind profiles at several radii from the low-level circulation center indicate that the magnitude of low-level circulation increases and that the corresponding tangential velocity maximum moves inward from the first to second reconnaissance mission. To compliment these findings, a three-dimensional variational analysis incorporating both dropwindsonde and aircraft Doppler radar data is conducted. These data are used to perform circulation tendency calculations at multiple distances from the low-level circulation center. The results demonstrate a net spin-up of the system-scale circulation in the low-levels near the center and in the outer regions of the recirculating Kelvin cat's eye circulation. In these regions, the spin-up tendency due to the influx of cyclonic absolute vorticity exceeds the frictional spin-down tendency for both Nuri missions. The system-scale spin up is found to be accompanied by areas of low-level vorticity concentration through vortex-tube stretching associated with cumulus convection. The areal coverage and intensity of these high-vorticity regions increase between the first and second Nuri missions. The findings of this study are consistent in some respects to the Nuri observational analysis carried out by Raymond and Lopez (2011), but differ in their suggested key result and related scientific implication that the pre-Nuri disturbance was spinning down on the first day of observations. The findings herein strongly support a recent tropical cyclogenesis model positing that the Kelvin cat's eye circulation of the parent wave-like disturbance provides a favorable environment for convective-vorticity organization and low-level spin-up on the mesoscale.
A novel Whole Air Sample Profiler (WASP) for the quantification of volatile organic compounds in the boundary layer
Authors: Mak J. E. , Su L. , Guenther A. , Karl T.
Published: October 2013

Abstract. The emission and fate of reactive volatile organic compounds (VOCs) is of inherent interest to those studying chemical biosphere–atmosphere interactions. In-canopy VOC observations are obtainable using tower-based samplers, but the lack of suitable sampling systems for the full boundary layer has limited the availability of data characterizing the vertical structure of such gases above the canopy height and still in the boundary layer. This is an important region where many reactive VOCs are oxidized or otherwise removed. Here we describe an airborne sampling system designed to collect a vertical profile of air into a 3/8 in. OD (outer diameter) tube 150 m in length. The inlet ram air pressure is used to flow sampled air through the tube, which results in a varying flow rate based on aircraft speed and altitude. Since aircraft velocity decreases during ascent, it is necessary to account for the variable flow rate into the tube. This is accomplished using a reference gas that is pulsed into the air stream so that the precise altitude of the collected air can be reconstructed post-collection. The pulsed injections are also used to determine any significant effect from diffusion/mixing within the sampling tube, either during collection or subsequent extraction for gas analysis. This system has been successfully deployed, and we show some measured vertical profiles of isoprene and its oxidation products methacrolein and methyl vinyl ketone from a mixed canopy near Columbia, Missouri.
Extracting gravity wave parameters during the September 2002 Southern Hemisphere major sudden stratospheric warming using a SANAE imaging riometer
Authors: Mbatha N. , Sivakumar V. , Bencherif H. , Malinga S.
Published: October 2013

Abstract. Using absorption data measured by imaging riometer for ionospheric studies (IRIS) located at the South Africa National Antarctic Expedition (SANAE), Antarctica (72° S, 3° W), we extracted the parameters of gravity waves (GW) of periods between 40 and 50 min during late winter/spring of the year 2002, a period of the unprecedented major sudden stratospheric warming (SSW) in the Southern Hemisphere middle atmosphere. During this period, an unprecedented substantial increase of temperature by about 25–30 K throughout the stratosphere was observed. During the period of the occurrence of the major stratospheric warming, there was a reduction of both the GW horizontal phase speeds and the horizontal wavelengths at 90 km. The GW phase speeds and horizontal wavelengths were observed to reach minimum values of about 7 m s−1 and 19 km, respectively, while during the quiet period the average value of the phase speed and horizontal wavelength was approximately 23 m s−1 and 62 km, respectively. The observed event is discussed in terms of momentum flux and also a potential interaction of gravity waves, planetary waves and mean circulation.
Can the heterogeneity in stream dissolved organic carbon be explained by contributing landscape elements?
Authors: Ågren A. M. , Buffam I. , Cooper D. M. , Tiwari T. , Evans C. D. , Laudon H.
Published: October 2013

Abstract. The controls on stream dissolved organic carbon (DOC) concentrations were investigated in a 68 km2 catchment by applying a landscape-mixing model to test if downstream concentrations could be predicted from contributing landscape elements. The landscape-mixing model reproduced the DOC concentration well throughout the stream network during times of high discharge, but was even more useful for providing a baseline for residual analysis, which highlighted areas for further conceptual model development. The landscape-mixing model approach is conceptually simple and easy to apply, requiring relatively few field measurements and minimal parameterization. The residual analysis highlighted areas of the stream network that were not well represented by simple mixing of headwaters, as well as flow conditions during which simple mixing based on headwater watershed characteristics did not apply. Specifically, we found that during periods of base flow the larger valley streams underlain by fine sorted sediments had much lower DOC concentrations than would be predicted by simple mixing; while peatland streams had higher DOC than predicted. During periods of intermediate and high flow the model made more accurate predictions of downstream DOC. Our interpretation is that the higher degree of hydrological connectivity during high flows, possibly combined with shorter stream residence times, increased the predictive power of this whole-watershed based mixing model. However, there was still a clear pattern during high discharge periods, with peatland streams having lower DOC than would be predicted by simple mixing while forested streams had higher DOC. These observations suggest several potential mechanisms to be further explored using more focused field and process-based modeling studies, especially on the role of changing hydrological pathways.
Causes of Greenland temperature variability over the past 4000 yr: implications for northern hemispheric temperature changes
Authors: Kobashi T. , Goto-Azuma K. , Box J. E. , Gao C.-C. , Nakaegawa T.
Published: October 2013

Abstract. Precise understanding of Greenland temperature variability is important in two ways. First, Greenland ice sheet melting associated with rising temperature is a major global sea level forcing, potentially affecting large populations in coming centuries. Second, Greenland temperatures are highly affected by North Atlantic Oscillation/Arctic Oscillation (NAO/AO) and Atlantic multidecadal oscillation (AMO). In our earlier study, we found that Greenland temperature deviated negatively (positively) from northern hemispheric (NH) temperature trend during stronger (weaker) solar activity owing to changes in atmospheric/oceanic changes (e.g. NAO/AO) over the past 800 yr (Kobashi et al., 2013). Therefore, a precise Greenland temperature record can provide important constraints on the past atmospheric/oceanic circulation in the region and beyond. Here, we investigated Greenland temperature variability over the past 4000 yr reconstructed from argon and nitrogen isotopes from trapped air in a GISP2 ice core, using a one-dimensional energy balance model with orbital, solar, volcanic, greenhouse gas, and aerosol forcings. The modelled northern Northern Hemisphere (NH) temperature exhibits a cooling trend over the past 4000 yr as observed for the reconstructed Greenland temperature through decreasing annual average insolation. With consideration of the negative influence of solar variability, the modelled and observed Greenland temperatures agree with correlation coefficients of r = 0.34–0.36 (p = 0.1–0.04) in 21 yr running means (RMs) and r = 0.38–0.45 (p = 0.1–0.05) on a centennial timescale (101 yr RMs). Thus, the model can explain 14 to 20% of variance of the observed Greenland temperature in multidecadal to centennial timescales with a 90–96% confidence interval, suggesting that a weak but persistent negative solar influence on Greenland temperature continued over the past 4000 yr. Then, we estimated the distribution of multidecadal NH and northern high-latitude temperatures over the past 4000 yr constrained by the climate model and Greenland temperatures. Estimated northern NH temperature and NH average temperature from the model and the Greenland temperature agree with published multi-proxy temperature records with r = 0.35–0.60 in a 92–99% confidence interval over the past 2000 yr. We found that greenhouse gases played two important roles over the past 4000 yr for the rapid warming during the 20th century and slightly cooler temperature during the early period of the past 4000 yr. Lastly, our analysis indicated that the current average temperature (1990–2010) or higher temperatures occurred at a frequency of 1.3 times per 1000 yr for northern high latitudes and 0.36 times per 4000 yr for NH temperatures, respectively, indicating that the current multidecadal NH temperature (1990–2010) is more likely unprecedented than not (p = 0.36) for the past 4000 yr.
High dimensional decision dilemmas in climate models
Authors: Bracco A. , Neelin J. D. , Luo H. , McWilliams J. C. , Meyerson J. E.
Published: October 2013

Abstract. An important source of uncertainty in climate models is linked to the calibration of model parameters. Interest in systematic and automated parameter optimization procedures stems from the desire to improve the model climatology and to quantify the average sensitivity associated with potential changes in the climate system. Building upon on the smoothness of the response of an atmospheric circulation model (AGCM) to changes of four adjustable parameters, Neelin et al. (2010) used a quadratic metamodel to objectively calibrate the AGCM. The metamodel accurately estimates global spatial averages of common fields of climatic interest, from precipitation, to low and high level winds, from temperature at various levels to sea level pressure and geopotential height, while providing a computationally cheap strategy to explore the influence of parameter settings. Here, guided by the metamodel, the ambiguities or dilemmas related to the decision making process in relation to model sensitivity and optimization are examined. Simulations of current climate are subject to considerable regional-scale biases. Those biases may vary substantially depending on the climate variable considered, and/or on the performance metric adopted. Common dilemmas are associated with model revisions yielding improvement in one field or regional pattern or season, but degradation in another, or improvement in the model climatology but degradation in the interannual variability representation. Challenges are posed to the modeler by the high dimensionality of the model output fields and by the large number of adjustable parameters. The use of the metamodel in the optimization strategy helps visualize trade-offs at a regional level, e.g., how mismatches between sensitivity and error spatial fields yield regional errors under minimization of global objective functions.
Precipitation and snow cover in the Himalaya: from reanalysis to regional climate simulations
Authors: Ménégoz M. , Gallée H. , Jacobi H. W.
Published: October 2013

Abstract. We applied a Regional Climate Model (RCM) to simulate precipitation and snow cover over the Himalaya, between March 2000 and December 2002. Due to its higher resolution, our model simulates a more realistic spatial variability of wind and precipitation than those of the reanalysis of the European Centre of Medium range Weather Forecast (ECMWF) used as lateral boundaries. In this region, we found very large discrepancies between the estimations of precipitation provided by reanalysis, rain gauges networks, satellite observations, and our RCM simulation. Our model clearly underestimates precipitation at the foothills of the Himalaya and in its eastern part. However, our simulation provides a first estimation of liquid and solid precipitation in high altitude areas, where satellite and rain gauge networks are not very reliable. During the two years of simulation, our model resembles the snow cover extent and duration quite accurately in these areas. Both snow accumulation and snow cover duration differ widely along the Himalaya: snowfall can occur during the whole year in western Himalaya, due to both summer monsoon and mid-latitude low pressure systems bringing moisture into this region. In Central Himalaya and on the Tibetan Plateau, a much more marked dry season occurs from October to March. Snow cover does not have a pronounced seasonal cycle in these regions, since it depends both on the quite variable duration of the monsoon and on the rare but possible occurrence of snowfall during the extra-monsoon period.