bluuebunny/crossref_metadata_2025 huggingface dataset:
Surgical treatment of thoracic Pott disease in a 3-year-old child, with vertebral column resection and posterior-only circumferential reconstruction of the spinal column
Authors: Rangel-Castilla Leonardo , Hwang Steven W. , Whitehead William E. , Curry Daniel J. , Luerssen Thomas G. , Jea Andrew
Published: March 2012

Tuberculosis (TB) is a common disease worldwide that is caused by Mycobacterium tuberculosis. Tuberculosis of the spine, also called Pott disease, is the most common site of bony dissemination. Although children are disproportionately affected, spinal TB is nonetheless rare in very young children. Cases involving infants requiring surgical intervention have been previously reported, and they are often associated with greater management challenges given the technical difficulty with instrumentation in very young children.

This case involved a 3-year-old girl with TB centered at T-6, who presented with myelopathy from spinal cord compression and a severe kyphotic deformity (> 60°). She underwent a single-stage costotransversectomy for vertebral column resection, followed by reconstruction with an anterior expandable titanium cage and posterior pedicle screw instrumentation. At last follow-up, the patient was clinically and radiographically stable.

The authors report on the youngest patient with spinal TB treated surgically with this strategy and review the literature regarding prior cases involving young children. Although limited by the paucity of cases in the literature, surgical debridement and spinal fusion appear to provide a safe alternative to prolonged bed rest or casting and may offer additional benefits of a faster recovery and ambulation.
Stereotactic endoscopic resection and surgical management of a subependymal giant cell astrocytoma
Authors: Rodgers Shaun D. , Bassani Luigi , Weiner Howard L. , Harter David H.
Published: March 2012

Subependymal giant cell astrocytomas (SEGAs) are benign tumors, most commonly associated with tuberous sclerosis complex (TSC). Arising from the lateral ependymal surface, these tumors may obstruct one or both foramina of Monro, resulting in hydrocephalus and often requiring treatment. Although interhemispheric-transcallosal and transcortical-transventricular approaches have been the standard methods for resecting these tumors, advances in neuroendoscopic techniques have expanded SEGAs as a potential target for endoscopic resection.

The authors present a case of an endoscopically resected SEGA with stereotactic guidance in a 4-year-old girl with TSC. A gross-total resection of an enlarging SEGA was achieved. This represents one of the early case reports of endoscopically resected SEGAs. Although recent advances in medical treatment for SEGAs with mammalian target of rapamycin (mTOR) pathway inhibitors have shown promising initial results, the long-term safety and efficacy of mTOR inhibitors has yet to be determined. The propensity of these tumors to cause obstructive hydrocephalus requires that a surgical option remain. Neuroendoscopic approaches may allow a safe and effective technique.
Cerebrospinal fluid shunting and hearing loss in patients treated for medulloblastoma
Authors: Guillaume Daniel J. , Knight Kristin , Marquez Carol , Kraemer Dale F. , Bardo Dianna M. E. , Neuwelt Edward A.
Published: March 2012

Object

Cerebrospinal fluid shunting has previously been associated with hearing loss. Although the mechanism for this is unclear, it is thought that changes in CSF pressure can affect cochlear physiology via endolymph expansion in the setting of a patent cochlear aqueduct. Patients undergoing radiation and cisplatin chemotherapy are at risk for hearing loss. The authors hypothesized that the incidence and severity of hearing loss in patients undergoing radiation and chemotherapy for medulloblastoma would be greater in those with shunts than in those without shunts.

Methods

Baseline and longitudinal audiology data were collected in 33 patients with medulloblastoma who were receiving radiation and cisplatin chemotherapy. Additional data included age, sex, details of shunt placement and revision, and details of chemotherapy and radiation. Hearing sensitivity and peripheral auditory function measures included pure tone audiometry, immittance audiometry, and distortion product evoked otoacoustic emissions. Ototoxicity was determined according to the American Speech-Language-Hearing Association criteria. Severity of hearing loss was determined using the Brock hearing loss grades. Incidence of hearing loss and association with shunting was determined.

Results

Thirteen (39.4%) of the 33 patients evaluated had undergone shunt placement. Hearing loss occurred in 14 (70%) of 20 patients without shunts and in 13 (100%) of 13 patients with shunts. The difference between the rates of hearing loss in patients with shunts versus those without the devices was highly significant (p = 0.0008). The odds ratio for hearing loss in patients with a CSF shunt compared with those without a shunt was 23.49 (95% CI 4.21–131.15). Age, side of shunt, evidence of dissemination, diameter of cochlear aqueduct, and treatment protocol did not have a significant effect on shunt-related ototoxicity.

Conclusions

This study suggests an independent association between CSF shunting and hearing loss in children undergoing treatment for medulloblastoma, laying the foundation for a prospective study evaluating hearing loss in children with shunts who are not treated with ototoxic therapy.
Improved survival following cerebral edema using a novel hollow fiber-hydrogel device
Authors: McBride Devin W. , Hsu Mike S. , Rodgers Victor G. J. , Binder Devin K.
Published: March 2012

Object

Cerebral edema is a significant cause of morbidity and mortality in many disease states. Current therapies of cerebral edema are often ineffective in treating severe edema. Here, the authors develop a hollow fiber-hydrogel device (HFHD) for direct surface contact–based treatment of severe cerebral edema.

Methods

Brain edema was induced in adult mice via water intoxication by intraperitoneal water administration (30% body weight). Control mice received no treatment. A distinct group of mice was treated with craniectomy but no device application (craniectomy only). A third experimental group was treated with craniectomy and HFHD application. The HFHD contained a lumen solution of 350 g/L bovine serum albumin in room-temperature artificial CSF at pH 7.4. Survival and brain water content were assessed as end points.

Results

Craniectomy and application of the HFHD enhanced survival in animals with severe cerebral edema. Animals treated with a craniectomy and HFHD (n = 5) survived up to 5 hours longer than animals treated with craniectomy only (n = 5) (p < 0.001) or no treatment (n = 5) (p < 0.001). Animals treated with craniectomy and HFHD (n = 5) had a survival rate of 80% within the observation period (360 minutes), whereas no animal treated with craniectomy only (n = 5) or no treatment (n = 5) survived longer than 50 and 33 minutes, respectively. Statistical significance was observed for the survival rate between the animals treated with a craniectomy + HFHD (n = 5) versus those treated with craniectomy only (n = 5) (p < 0.001), and craniectomy + HFHD versus no treatment (n = 5) (p < 0.001). Histological analysis demonstrated no significant cell loss in the cortex subjacent to HFHD application.

Conclusions

Here, the authors demonstrate the feasibility of their HFHD to treat cerebral edema in this model. These results indicate that controlled water extraction from edematous brain tissue can be performed and can lead to increased survival compared with craniectomy only. Further studies remain to be performed to further optimize the HFHD and to test it in more clinically relevant models, such as traumatic brain injury.
The effects of carpentry on heterotopic ossification and mobility in cervical arthroplasty: determination by computed tomography with a minimum 2-year follow-up
Authors: Tu Tsung-Hsi , Wu Jau-Ching , Huang Wen-Cheng , Wu Ching-Lan , Ko Chin-Chu , Cheng Henrich
Published: March 2012

Object

Heterotopic ossification (HO) after cervical arthroplasty can limit the mobility of an artificial disc. In this study the authors used CT scanning to assess the formation of HO with the goal of investigating the correlation between the carpentry of arthroplasty, formation of HO, mobility, and clinical outcomes.

Methods

A retrospective review of medical records, radiological studies, and clinical evaluations was conducted for consecutive patients who underwent 1- or 2-level cervical arthroplasty with the Bryan disc. The patients underwent follow-up for more than 24 months. The formation of HO was assessed using CT scanning as the final determination. The perfectness of carpentry for each arthroplasty level was scrutinized using criteria composed of 2 parameters (postoperative shell kyphosis and inadequate endplate coverage). Levels were divided into the optimal carpentry group and the suboptimal carpentry group. Radiographic and clinical outcomes, including the visual analog scale and neck disability index, were compared between the groups.

Results

A total of 107 levels of Bryan discs were placed in 75 patients (mean age 46.71 ± 9.94 years) and were analyzed. There was a male predominance of 68.0% (51 men), and the mean follow-up duration was 38.56 ± 9.66 months. Heterotopic ossification was identified in 60 levels (56.1%) by CT scanning. Most cases of HO were low grade and did not correlate with the limitation in the segmental motion of the arthroplasty device. There were no significant differences in terms of age, sex, and number of arthroplasty levels between the optimal and the suboptimal carpentry groups. However, the suboptimal carpentry group had significantly more high-grade HO (≥ Grade 2) than the optimal carpentry group (13 levels [12.1%] vs 7 levels [6.5%], p = 0.027). There were also more immobile (range of motion < 3°) artificial discs in the suboptimal carpentry group than the optimal carpentry group (11 levels [10.3%] vs 4 levels [3.7%], p = 0.010). The clinical outcomes (neck and arm visual analog scale scores and Neck Disability Index) in both groups were similarly good.

Conclusions

Shell kyphosis and inadequate endplate coverage have adverse effects on the formation of HO and segmental mobility after cervical arthroplasty with the Bryan artificial disc. Appropriate carpentry is the more important factor in determining the maintenance of segmental motion. Although the midterm clinical outcome remained similarly good regardless of HO, the carpentry of cervical arthroplasty should not be overlooked. Further studies are needed to clarify the etiology of HO.
An Environmental Impact Study of Jamuna Urea Fertilizer Factory at
Authors: Samad MA , Ali MI , Paul D , Islam SMA
Published: March 2012

The activity concentrations of 226Ra, 232Th and 40K have been determined in solid and liquid samples collected from the Jamuna Urea Fertilizer Factory, Tarakandi, Jamalpur, Bangladesh. Six different types of samples, namely, i) the liquid waste water stored inside the factory ii) water sample near the liquid waste disposal point of Jamuna river iii) liquid-waste-mixed soil iv) normal soil adjacent to the factory v) the final product (Urea) and vi) urea dust of the factory have been analyzed by gamma spectrometric technique using a high purity germanium (HPGe) detector of 40% relative efficiency. The activity concentration of 226Ra was determined from the average concentrations of the 214Pb and 214Bi decay products, the activity concentration of 232Th was determined from the average concentrations of 208Tl and 228Ac, whereas the concentration of 40K was measured directly. The analysis of the liquid waste samples showed that the average activity concentrations of 226Ra and 232Th were 3.64 ± 0.72 and 12.94 ± 2.02 Bq/L, respectively and no 40K was detected in any of the samples. In the liquid-waste-mixed soil samples the average value of activity concentrations of 226Ra, 232Th and 40K were 21.45 ± 3.19, 63.00 ± 8.10 and 311.97 ± 90.93 Bq/kg, respectively whereas in the normal soil the values were 20.97 ± 3.56, 61.77 ± 8.93 and 645.48 ± 103.62 Bq/kg, respectively. Considering the stored wastes as a part of the ambient environment of the factory, radium equivalent activity, radiation hazard index and external annual effective dose to the worker and the public due to these wastes were calculated and compared with the world average values.DOI: http://dx.doi.org/10.3329/jesnr.v4i2.10131J. Environ. Sci. & Natural Resources, 4(2): 27-33, 2011
Bio-efficacy of Acetochlor 50% EC against Weed Suppression in
Authors: Mamun MAA , Mridha AJ , Akter A , Parvez A
Published: March 2012

Field experiments were conducted at Bangladesh Rice Research Institute (BRRI), Gazipur in Aus, 2010 and BRRI Rangpur, during Boro 2011 to evaluate the performance of Acetochlor 50% EC for weed suppression, to find out an appropriate dose of the herbicide and its impacts on transplanted rice. Acetochlor 50%EC @ 200, 250 and 300 ml ha-1 were applied. Pretilachlor 50% EC @ 1L ha-1, weed free and unweeded control was used for comparison. The most dominant weeds were Cyperus diffornis, Monochoria vaginalis and Echinochloa crus-galli in year 1 and Cyperus diffornis and Echinochloa crus-galli in year 2. Cyperus diffornis was at the higher rank of dominant in both years. Application of Acetochlor 50%EC @ 250 ml gave more than 80% weed control efficiency, lower number and dry weight of weeds which ultimately resulted in higher yield attributes and grain yield of transplanted rice that were comparable to the standard in both seasons.DOI: http://dx.doi.org/10.3329/jesnr.v4i2.10137  J. Environ. Sci. & Natural Resources, 4(2): 73-77, 2011
Integrated Farming System: Prospects in Bangladesh
Authors: Al Mamun Shamim , Nasrat Fouzia , Debi Momota Rani
Published: March 2012

Farmers of Bangladesh generally practice subsistence farming where they need to produce a continuous, reliable and balanced supply of foods, as well as cash for basic needs and recurrent farm expenditure. Therefore, there is a need to develop suitable integrated farming systems for such farmers since single crop production enterprises are subject to a high degree of risk and uncertainty because of seasonal, irregular and uncertain income and employment to the farmers. Integrated Farming System (IFS) can eradicate all these constraints by not only solving most of the existing economic and even ecological problems, but also provide other household needs like fuel, fertilizer and feed, besides increasing productivity of the farm manifold.DOI: http://dx.doi.org/10.3329/jesnr.v4i2.10161  J. Environ. Sci. & Natural Resources, 4(2): 127-136, 2011
Effect of Urea Super Granule on Growth and Yield of Wheat
Authors: Islam MS , Biswas GC , Karmoker MC , Suem MA
Published: March 2012

A field experiment was carried out at Agronomy Field, Bangladesh Agricultural University (BAU), Mymensingh during the period from November 2009 to March 2010 with a view to finding out the effect of appropriate dose of USG on growth and yield of wheat. Six levels of nitrogen (T0, T1, T2, T3, T4 and T5) were applied as treatments for growth and yield of wheat var. Bijoy for this study. Among the application of USG, treatment T5 produced the superior results on morpho-physiological and growth characters of wheat except number of non sterile spikelet where USG treatment T2 performs the best (1.82). As results, T5 produced the highest plant height (95.77 cm), number of total tiller hill-1 (4.96), no. of effective tiller (4.13), no of non effective tiller (1.00), number of total spikelet (20.22), no of spikelet spile-1 (10.92), sterile spieklet (18.70), no of grains spike-1 (46.27), 1000-grain yield (51.39 g), grain yield (2.42 t ha-1) and straw yield (4.06 tha-1).DOI: http://dx.doi.org/10.3329/jesnr.v4i2.10164  J. Environ. Sci. & Natural Resources, 4(2): 143-146, 2011
Climatic Variables of 50 Years and their Trends over Rajshahi and Rangpur Division
Authors: Ferdous MG , Baten MA
Published: March 2012

An agro-climatic study was conducted at three regions of Rajshahi division with 50 (1961-2010) years of climatic data (temperature, rainfall, relative humidity and sunshine) to observe the climatic variability. The annual average temperature was showed decreasing trends over Rajshahi, Rangpur and Dinajpur regions by 0.0134, 0.0262 and 0.01180C/year. Annual average rainfall showed increasing trends over Rangpur and Dinajpur region by 14.971, 18.673mm/year and decreasing trends over Rajshahi region by 3.0698mm/year. Average relative humidity was showed increasing trends over Rajshahi, and Dinajpur region by 0.0261, and 0.0269%/year. Over Rangpur region, the decreasing trend was observed by 0.0599%/year. Decreasing trends of sunshine were observed for all regions. Distributions of regional average of climate factors in the study area were observed TRangpur> TRajshahi> TDinajpur, RRangpur> RDinajpur> RRajshahi, RHRangpur> RHDinajpur> RHRajshahi and SDinajpur> SRajshahi> SRangpur for temperature, rainfall, relative humidity and sunshine, respectively.DOI: http://dx.doi.org/10.3329/jesnr.v4i2.10165J. Environ. Sci. & Natural Resources, 4(2): 147-150, 2011
Honour, Honours and Nobility in Scotland between the Reformation and the National Covenant
Authors: Brown Keith M.
Published: March 2012

Honour is a currency found in most pre-modern communities. In early modern Europe the version of honour that predominated in male, noble societies was commonly associated with martial attributes and the reputation of the kindred, the lineage and its living representatives. The competitive nature of noble houses, and the intense sensitivity of individual nobles and their men to insult, often led to violence in the form of duels and feuds. In later sixteenth-century Scotland, where feuding was especially prevalent, this version of honour was closely associated with acts of personal and group conflict that fuelled political instability. Alternative versions of honour derived from ideas about virtue were promoted by humanist thinkers, the new Protestant church which wished to promote ideas of godly behaviour, and the crown which advocated a concept of honour derived from the king. The regal union of 1603 altered Scotland's political landscape, increasing the wealth of the crown and allowing James VI and Charles I to use their enhanced patronage to promote their version of honour, especially through an expansion of honours. The parallel reduction in feuding weakened the association of honour with violence. However, the crown's rhetoric was superficial and noble society remained wedded to a concept of honour that embraced notions of personal virtue alongside martial behaviour, and rooted in the reputation of the lineage rather than in service to the prince. The ultimate rejection of the latter was demonstrated in the overthrow of royal authority in the Covenanting revolution of 1637.
The Bubble on the Periphery: Scotland and the South Sea Bubble
Authors: Walsh Patrick
Published: March 2012

The South Sea bubble of 1720 has traditionally been seen as a London-centric event, with its impact on the British peripheries of Ireland and Scotland being largely ignored. This article examines the Scottish context of the bubble, looking at Scottish investment in London, the reactions of Scots to the rise and fall of the Company, and its impact on Scottish projects and schemes. Drawing on a range of manuscript and printed sources, and through the exploration of individual case studies, this article demonstrates that the Scottish experience of the financial revolution extended beyond the collapse of the Darien project and the Act of Union. The findings presented here suggest a need to revisit both the historiography of the bubble and the financial history of post-Union Scotland.
Stem alternations and multiple exponence
Authors: Baerman Matthew , Corbett Greville G.
Published: March 2012

In a canonical inflectional paradigm, inflectional affixes mark distinctions in morphosyntactic value, while the lexical stem remains invariant. But stems are known to alternate too, constituting a system of inflectional marking operating according to parameters which typically differ from those of the affixal system, and so represent a distinct object of inquiry. Cross-linguistically, we still lack a comprehensive picture of what patterns of stem alternation are found, and hence the theoretical status of stem alternations remains unclear. We propose a typological framework for classifying stem alternations, basing it on the paradigm-internal relationship between the features marked by stem alternations versus those marked by affixes. Stem alternations may mark completely different features from the affixes (§2), or the same features (§3). Within the latter, the values may match (§3.1) – a rare situation – or be conflated (§3.2). Conflation in turn may involve natural semantic/morphosyntactic classes (§3.2.1), or phonological conditioning (§3.2.2), or be morphologically stipulated (§3.2.3). These patterns typically reveal stems’ continued allegiance to lexical as opposed to inflectional organizing principles.
Identifying Stems
Authors: Spencer Andrew
Published: March 2012

Programmatic proposals are presented for identifying the boundary between stem and affix in morphologically complex words. This is part of the wider, largely unresearched, problem of segmenting words into morphs. Two principles are proposed for expediting stem segmentation: the Strictly Morphomic Stem Hypothesis (‘all stems are morphomic’) and the Stem Maximization Principle (‘a putative inflection must unambiguously realize a coherent set of morphosyntactic properties, otherwise it is part of a morphomic stem’). It is proposed that there should be a separate stem formation component with essentially the same architecture as the inflectional component to define members of the stem space.1
Carotenoids, Fatty Acid Composition and Heat Stability of Supercritical Carbon Dioxide-Extracted-Oleoresins
Authors: Longo Cristiano , Leo Lucia , Leone Antonella
Published: March 2012

The risk of chronic diseases has been shown to be inversely related to tomato intake and the lycopene levels in serum and tissue. Cis-isomers represent approximately 50%–80% of serum lycopene, while dietary lycopene maintains the isomeric ratio present in the plant sources with about 95% of all-trans-lycopene. Supercritical CO2 extraction (S-CO2) has been extensively developed to extract lycopene from tomato and tomato processing wastes, for food or pharmaceutical industries, also by using additional plant sources as co-matrices. We compared two S-CO2-extracted oleoresins (from tomato and tomato/hazelnut matrices), which showed an oil-solid bi-phasic appearance, a higher cis-lycopene content, and enhanced antioxidant ability compared with the traditional solvent extracts. Heat-treating, in the range of 60–100 °C, led to changes in the lycopene isomeric composition and to enhanced antioxidant activity in both types of oleoresins. The greater stability has been related to peculiar lycopene isomer composition and to the lipid environment. The results indicate these oleoresins are a good source of potentially healthful lycopene.
On the Regulatory Approval Pathway of Biosimilar Products
Authors: Wang Jun , Chow Shein-Chung
Published: March 2012

Biosimilars (or follow-on biologics) are a new class of medicine which enters the market subsequent to a previously approved version. They have demonstrated similarity to innovator biologic products in terms of quality, safety, and efficacy. The EMA has taken the lead in the regulatory approval framework for biosimilar products, and WHO has published guidelines on the evaluation of biosimilars in order to facilitate the global harmonization. Based on EMA and WHO guidelines, many other countries such as Canada, Japan and Korea have also issued their own guidance for evaluating follow-on biologics. The US FDA was authorized to approve follow-on biologics by the BPCI Act passed by the US Congress on March 23, 2010, and has just issued a draft guidance in early 2012. The basic concepts and main principles of approving biosimilars are similar among various nations, notwithstanding some differences in regard to the scope, the choice of reference product, and the data requirement. This article reviews the regulatory approval pathway of biosimilar products in different regions.
A Vision Based Top-View Transformation Model for a Vehicle Parking Assistant
Authors: Lin Chien-Chuan , Wang Ming-Shi
Published: March 2012

This paper proposes the Top-View Transformation Model for image coordinate transformation, which involves transforming a perspective projection image into its corresponding bird’s eye vision. A fitting parameters searching algorithm estimates the parameters that are used to transform the coordinates from the source image. Using this approach, it is not necessary to provide any interior and exterior orientation parameters of the camera. The designed car parking assistant system can be installed at the rear end of the car, providing the driver with a clearer image of the area behind the car. The processing time can be reduced by storing and using the transformation matrix estimated from the first image frame for a sequence of video images. The transformation matrix can be stored as the Matrix Mapping Table, and loaded into the embedded platform to perform the transformation. Experimental results show that the proposed approaches can provide a clearer and more accurate bird’s eye view to the vehicle driver.
RESEARCH OF COMPETITIVE ENVIRONMENT OF KLAIPĖDA SEAPORT COMPARING TO OTHER SEAPORTS IN THE EASTERN BALTIC SEA REGION
Authors: Jarašūnienė Aldona , Greičiūnė Laima , Šakalys Algirdas
Published: March 2012

Constructive and systematic management of a seaport may determine its successful competitive ability in the international market. The analysis of competitive ability of Klaipėda Seaport highlighted its weakest points, influencing the overall competitiveness of the port. The encouragement of port competitive ability is often stressed, however, there is a lack of methodologically based competitive models that include all key factors determining port competitive ability. The current paper gives stages of evaluation both the significance of indices and the importance of criteria in the international market allowed us to determine factors that have an impact on port competitive ability mostly. The method, allowing to predict cargo flows, was used in the description of scenarios for the encouragement of port competitiveness. In order to ensure these cargo flows the port development is also concerned, as an integrated task, which would allow the evaluation of possible changes of cargo flows, port investments and influence of other ports on cargo flows, etc.
INCREASING THE CAPACITY OF INTERSECTIONS BY SHORT TRAFFIC LANES
Authors: Klibavičius Antanas , Paliulis Gražvydas Mykolas
Published: March 2012

When during peak hours intersections are loaded with 5000÷8000 veh/h, installation of short traffic lanes – one or two in each direction – is one of the most economical solutions for their reconstruction. Technical Construction Regulations (STR 2.06.01:1999) of Lithuania do not provide specific recommendations for calculation of the capacity of short traffic lanes. During 2005–2010, the authors of the article performed on-site tests of transport flows in the city of Vilnius and devised the methodology for modelling and calculation of short traffic lane capacity considering the size of the traffic flows. The article presents recommendations on calculation of lost time and vehicle queue lengths considering the size of traffic flows.
Type 1 Diabetes-Associated IL2RA Variation Lowers IL-2 Signaling and Contributes to Diminished CD4+CD25+ Regulatory T Cell Function
Authors: Garg Garima , Tyler Jennifer R. , Yang Jennie H. M. , Cutler Antony J. , Downes Kate , Pekalski Marcin , Bell Gwynneth L. , Nutland Sarah , Peakman Mark , Todd John A. , Wicker Linda S. , Tree Timothy I. M.
Published: March 2012

Numerous reports have demonstrated that CD4+CD25+ regulatory T cells (Tregs) from individuals with a range of human autoimmune diseases, including type 1 diabetes, are deficient in their ability to control autologous proinflammatory responses when compared with nondiseased, control individuals. Treg dysfunction could be a primary, causal event or may result from perturbations in the immune system during disease development. Polymorphisms in genes associated with Treg function, such as IL2RA, confer a higher risk of autoimmune disease. Although this suggests a primary role for defective Tregs in autoimmunity, a link between IL2RA gene polymorphisms and Treg function has not been examined. We addressed this by examining the impact of an IL2RA haplotype associated with type 1 diabetes on Treg fitness and suppressive function. Studies were conducted using healthy human subjects to avoid any confounding effects of disease. We demonstrated that the presence of an autoimmune disease-associated IL2RA haplotype correlates with diminished IL-2 responsiveness in Ag-experienced CD4+ T cells, as measured by phosphorylation of STAT5a, and is associated with lower levels of FOXP3 expression by Tregs and a reduction in their ability to suppress proliferation of autologous effector T cells. These data offer a rationale that contributes to the molecular and cellular mechanisms through which polymorphisms in the IL-2RA gene affect immune regulation, and consequently upon susceptibility to autoimmune and inflammatory diseases.
Expression of Functional P-Selectin Glycoprotein Ligand 1 on Hematopoietic Progenitors Is Developmentally Regulated
Authors: Sultana Dil Afroz , Zhang Shirley L. , Todd Sarah P. , Bhandoola Avinash
Published: March 2012

T cell development requires periodic importation of hematopoietic progenitors into the thymus. The receptor-ligand pair P-selectin and P-selectin glycoprotein ligand 1 (PSGL-1) are critically involved in this process. In this study, we examined the expression of functional PSGL-1 on bone marrow hematopoietic progenitors. We demonstrate that functional PSGL-1 is expressed at low levels on hematopoietic stem cells, but upregulated on the cell surface of progenitors that bear other homing molecules known to be important for thymic settling. We found that progenitors able to home to the thymus expressed high levels of PSGL-1 transcripts compared with hematopoietic stem cells. We further demonstrate that hematopoietic progenitors lacking fucosyltransferase 4 and 7 do not express functional PSGL-1, and do not home efficiently to the thymus. These studies provide insight into the developmentally regulated expression of a critical determinant involved in progenitor homing to the thymus.
Regular Potential Approximation for $\delta$-Perturbation Supported by Curve of the Laplace-Beltrami Operator on the Sphere
Authors: Eremin D.A. , Ivanov D.A. , Popov Igor Yu.
Published: March 2012

Operator extension theory model for

\delta

-perturbation supported by curve of the Laplace–Beltrami operator on the sphere is described. The sequence of operators with regular potentials converging to the model operator in norm resolvent sense is constructed.
Continuity and Differentiability of Multivalued Superposition Operators with Atoms and Parameters II
Authors: Väth Martin
Published: March 2012

For a given single- or multivalued function

f

and “atoms”

S_i

, let

S_f(\lambda,x)

be the set of all measurable selections of the function

s \mapsto f(\lambda, s, x(s))

which are constant on each

S_i

. It is discussed how this definition must be extended so that

S_f

can serve as a right-hand side for PDEs when one is looking for weak solutions in Sobolev spaces. Continuity and differentiability of the corresponding operators are studied.
Meteorological modes of variability for fine particulate matter (PM2.5) air quality in the United States: implications for PM2.5 sensitivity to climate change
Authors: Tai A. P. K. , Mickley L. J. , Jacob D. J. , Leibensperger E. M. , Zhang L. , Fisher J. A. , Pye H. O. T.
Published: March 2012

Abstract. We applied a multiple linear regression model to understand the relationships of PM2.5 with meteorological variables in the contiguous US and from there to infer the sensitivity of PM2.5 to climate change. We used 2004–2008 PM2.5 observations from ~1000 sites (~200 sites for PM2.5 components) and compared to results from the GEOS-Chem chemical transport model (CTM). All data were deseasonalized to focus on synoptic-scale correlations. We find strong positive correlations of PM2.5 components with temperature in most of the US, except for nitrate in the Southeast where the correlation is negative. Relative humidity (RH) is generally positively correlated with sulfate and nitrate but negatively correlated with organic carbon. GEOS-Chem results indicate that most of the correlations of PM2.5 with temperature and RH do not arise from direct dependence but from covariation with synoptic transport. We applied principal component analysis and regression to identify the dominant meteorological modes controlling PM2.5 variability, and show that 20–40% of the observed PM2.5 day-to-day variability can be explained by a single dominant meteorological mode: cold frontal passages in the eastern US and maritime inflow in the West. These and other synoptic transport modes drive most of the overall correlations of PM2.5 with temperature and RH except in the Southeast. We show that interannual variability of PM2.5 in the US Midwest is strongly correlated with cyclone frequency as diagnosed from a spectral-autoregressive analysis of the dominant meteorological mode. An ensemble of five realizations of 1996–2050 climate change with the GISS general circulation model (GCM) using the same climate forcings shows inconsistent trends in cyclone frequency over the Midwest (including in sign), with a likely decrease in cyclone frequency implying an increase in PM2.5. Our results demonstrate the need for multiple GCM realizations (because of climate chaos) when diagnosing the effect of climate change on PM2.5, and suggest that analysis of meteorological modes of variability provides a computationally more affordable approach for this purpose than coupled GCM-CTM studies.
Airborne intercomparison of HOx measurements using laser-induced fluorescence and chemical ionization mass spectrometry during ARCTAS
Authors: Ren X. , Mao J. , Brune W. H. , Cantrell C. A. , Mauldin III R. L. , Hornbrook R. S. , Kosciuch E. , Olson J. R. , Crawford J. H. , Chen G. , Singh H. B.
Published: March 2012

Abstract. The hydroxyl (OH) and hydroperoxyl (HO2) radicals, collectively called HOx, play central roles in tropospheric chemistry. Accurate measurements of OH and HO2 are critical to examine our understanding of atmospheric chemistry. Intercomparisons of different techniques for detecting OH and HO2 are vital to evaluate their measurement capabilities. Three instruments that measured OH and/or HO2 radicals were deployed on the NASA DC-8 aircraft throughout Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS), in the spring and summer of 2008. One instrument was the Penn State Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) for OH and HO2 measurements based on Laser-Induced Fluorescence (LIF) spectroscopy. A second instrument was the NCAR Selected-Ion Chemical Ionization Mass Spectrometer (SI-CIMS) for OH measurement. A third instrument was the NCAR Peroxy Radical Chemical Ionization Mass Spectrometer (PeRCIMS) for HO2 measurement. Formal intercomparison of LIF and CIMS was conducted for the first time on a same aircraft platform. The three instruments were calibrated by quantitative photolysis of water vapor by UV light at 184.9 nm with three different calibration systems. The absolute accuracies were ±32% (2σ) for the LIF instrument, ±65% (2σ) for the SI-CIMS instrument, and ±50% (2σ) for the PeRCIMS instrument. In general, good agreement was obtained between the CIMS and LIF measurements of both OH and HO2 measurements. Linear regression of the entire data set yields [OH]CIMS = 0.89 × [OH]LIF + 2.8 × 105 cm−3 with a correlation coefficient, r2 = 0.72 for OH and [HO2]CIMS = 0.86 × [HO2]LIF + 3.9 parts per trillion by volume (pptv, equivalent to pmol mol−1) with a correlation coefficient, r2 = 0.72 for HO2. In general, the difference between CIMS and LIF instruments for OH and HO2 measurements can be explained by their combined measurement uncertainties. Comparison with box model results shows some similarities for both the CIMS and LIF measurements. First, the observed-to-modeled HO2 ratio increases greatly for higher NO mixing ratios, indicating that the model may not properly account for HOx sources that correlate with NO. Second, the observed-to-modeled OH ratio increases with increasing isoprene mixing ratios, suggesting either incomplete understanding of isoprene chemistry in the model or interferences in the measurements in environments where biogenic emissions dominate ambient volatile organic compounds.
Eddy Covariance flux measurements with a weight-shift microlight aircraft
Authors: Metzger S. , Junkermann W. , Mauder M. , Beyrich F. , Butterbach-Bahl K. , Schmid H. P. , Foken T.
Published: March 2012

Abstract. The objective of this study is to assess the feasibility and quality of Eddy-Covariance flux measurements from a weight-shift microlight aircraft (WSMA). Firstly we investigate the precision of the wind measurement (σu,v≤ 0.09 m s−1, σw = 0.04 m s−1), the lynchpin of flux calculations from aircraft. From here the smallest resolvable changes in friction velocity (0.02 m s−1), and sensible- (5 W m−2) and latent (3 W m−2) heat flux are estimated. Secondly a seven-day flight campaign was performed near Lindenberg (Germany). Here we compare measurements of wind, temperature, humidity and respective fluxes between a tall tower and the WSMA. The maximum likelihood functional relationship (MLFR) between tower and WSMA measurements considers the random error in the data, and shows very good agreement of the scalar averages. The MLFRs for standard deviations (SDs, 2–34%) and fluxes (17–21%) indicate higher estimates of the airborne measurements compared to the tower. Considering the 99.5% confidence intervals the observed differences are not significant, with exception of the temperature SD. The comparison with a large-aperture scintillometer reveals lower sensible heat flux estimates at both, tower (−40–−25%) and WSMA (−25–0%). We relate the observed differences to (i) inconsistencies in the temperature and wind measurement at the tower and (ii) the measurement platforms differing abilities to capture contributions from non-propagating eddies. These findings encourage the use of WSMA as a low price and highly versatile flux measurement platform.
The marine sedimentary nitrogen isotope record
Authors: Tesdal J. E. , Galbraith E. D. , Kienast M.
Published: March 2012

Abstract. A global database of nitrogen isotope data from marine sediments is presented, including both seafloor and sub-seafloor sediment samples. The data synthesis reveals regionally and globally consistent patterns and trends, with good agreement between neighbouring seafloor sites. The spatial coverage of seafloor δ15N data is heterogenous, with excellent coverage in the eastern tropical Pacific, South China Sea and Arabian Sea, while large regions of the globe remain unsampled. The sub-seafloor δ15N records are mostly from the late Pleistocene, with >90 coeval records during the last ~10 kiloyears (kyr), before which the number of records at any time decreases, with <10 coeval records at any time prior to 300 kyr. There is a good correlation between seafloor and shallow-subseafloor δ15N measurements within a 100 km radius, which suggest a reliable translation of sediments into the buried sediment record. We suggest that regional discrepancies between seafloor and late Holocene subseafloor δ15N indicate nitrogen cycle changes during the late Holocene period, rather than systematic diagenetic changes.
High temporal and spatial variability of dissolved oxygen and pH in a nearshore California kelp forest
Authors: Frieder C. A. , Nam S. H. , Martz T. R. , Levin L. A.
Published: March 2012

Abstract. Predicting consequences of ocean deoxygenation and ocean acidification for nearshore marine ecosystems requires baseline dissolved oxygen (DO) and carbonate chemistry data that are both high-frequency and high-quality. Such data allow accurate assessment of environmental variability and present-day organism exposure regimes. In this study, scales of DO and pH variability were characterized over one year in a nearshore, kelp forest ecosystem in the Southern California Bight. DO and pH were strongly, positively correlated revealing that organisms on this upwelling shelf are not only exposed to low pH but also low DO. The dominant temporal scale of DO and pH variability occurred on semidiurnal, diurnal and event (days–weeks) time scales. Daily ranges in DO and pH at 7 m water depth (13 mab) could be as large as 220 μmol kg−1 and 0.36 units, respectively. This range is much greater than the expected decreases in pH in the open ocean by the year 2100. Sources of pH and DO variation include photosynthesis within the kelp forest ecosystem, which can elevate DO and pH by up to 60 μmol kg−1 and 0.1 units over one week following the intrusion of high-density, nutrient-rich water. Accordingly, highly productive macrophyte-based ecosystems could serve as deoxygenation and acidification refugia by acting to elevate DO and pH relative to surrounding waters. DO and pH exhibited greater spatial variation over a 10 m increase in water depth (from 7 to 17 m) than along a 5-km stretch of shelf in a cross-shore or alongshore direction. Over a three-month time period mean DO and pH at 17-m water depth were 168 μmol kg−1 and 7.87, respectively. These values represent a 35% decrease in mean DO and 37% increase in [H+] relative to surface waters. High-frequency variation was also reduced at depth. The mean daily range in DO and pH was 39% and 37% less, respectively, at 17-m water depth relative to the surface. As a consequence, the exposure history of an organism is largely a function of its depth of occurrence within the kelp forest. These findings raise the possibility that the benthic communities along eastern boundary current systems are currently acclimatized and adapted to natural, variable, and low DO and pH. Future exposure of coastal California populations to low DO and pH may increase as upwelling intensifies and hypoxic boundaries shoal, compressing habitats and challenging the physiological capacity of intolerant species.
Precipitation changes in the South American Altiplano since 1300 AD reconstructed by tree-rings
Authors: Morales M. S. , Christie D. A. , Villalba R. , Argollo J. , Pacajes J. , Silva J. S. , Alvarez C. A. , Llancabure J. C. , Soliz Gamboa C. C.
Published: March 2012

Abstract. Throughout the second half of the 20th century, the Central Andes has experienced significant climatic and environmental changes characterized by a persistent warming trend, an increase in elevation of the 0 °C isotherm, and sustained glacier shrinkage. These changes have occurred in conjunction with a steadily growing demand for water resources. Given the short span of instrumental hydroclimatic records in this region, longer time span records are needed to understand the nature of climate variability and to improve the predictability of precipitation, a key factor modulating the socio-economic development in the South American Altiplano and adjacent arid lowlands. In this study we present the first quasi-millennial, tree-ring based precipitation reconstruction for the South American Altiplano. This annual (November–October) precipitation reconstruction is based on the Polylepis tarapacana tree-ring width series and represents the closest dendroclimatological record to the Equator in South America. This high-resolution reconstruction covers the past 707 yr and provides a unique record characterizing the occurrence of extreme events and consistent oscillations in precipitation. It also allows an assessment of the spatial and temporal stabilities of the teleconnections between rainfall in the Altiplano and hemispheric forcings such as El Niño-Southern Oscillation. Since the 1930s to present, a persistent negative trend in precipitation has been recorded in the reconstruction, with the three driest years since 1300 AD occurring in the last 70 yr. Throughout the 707 yr, the reconstruction contains a clear ENSO-like pattern at interannual to multidecadal time scales, which determines inter-hemispheric linkages between our reconstruction and other precipitation sensitive records modulated by ENSO in North America. Our reconstruction points out that century-scale dry periods are a recurrent feature in the Altiplano climate, and that the future potential coupling of natural and anthropogenic-induced droughts may have a severe impact on socio-economic activities in the region. Water resource managers must anticipate these changes in order to adapt to future climate change, reduce vulnerability and provide water equitably to all users.
A multi-proxy perspective on millennium-long climate variability in the Southern Pyrenees
Authors: Morellón M. , Pérez-Sanz A. , Corella J. P. , Büntgen U. , Catalán J. , González-Sampériz P. , González-Trueba J. J. , López-Sáez J. A. , Moreno A. , Pla-Rabes S. , Saz-Sánchez M. Á. , Scussolini P. , Serrano E. , Steinhilber F. , Stefanova V. , Vegas-Vilarrúbia T. , Valero-Garcés B.
Published: March 2012

Abstract. This paper reviews multi-proxy paleoclimatic reconstructions with robust age-control derived from lacustrine, dendrochronological and geomorphological records and characterizes the main environmental changes that occurred in the Southern Pyrenees during the last millennium. Warmer and relatively arid conditions prevailed during the Medieval Climate Anomaly (MCA, ca. 900–1300 AD), with a significant development of xerophytes and Mediterranean vegetation and limited deciduous tree formations (mesophytes). The Little Ice Age (LIA, 1300–1800 AD) was generally colder and moister, with an expansion of deciduous taxa and cold-adapted montane conifers. Two major phases occurred within this period: (i) a transition MCA–LIA, characterized by fluctuating, moist conditions and relatively cold temperatures (ca. 1300 and 1600 AD); and (ii) a second period, characterized by the coldest and most humid conditions, coinciding with maximum (recent) glacier advances (ca. 1600–1800 AD). Glaciers retreated after the LIA when warmer and more arid conditions dominated, interrupted by a short-living cooling episode during the late 19th to early 20th centuries. Some records suggest a response to solar activity with colder and slightly moister conditions during solar minima. Centennial-scale hydrological fluctuations are in phase with reconstructions of NAO variability, which appears to be one of the main climate mechanisms influencing rainfall variations in the region during the last millennium.
Comment on "Clouds and the Faint Young Sun Paradox" by Goldblatt and Zahnle (2011)
Authors: Rondanelli R. , Lindzen R. S.
Published: March 2012

Abstract. Goldblatt and Zahnle (2011) raise a number of issues related to the possibility that cirrus clouds can provide a solution to the faint young sun paradox. Here, we argue that: (1) climates having a lower than present mean surface temperature cannot be discarded as solutions to the faint young sun paradox, (2) the detrainment from deep convective clouds in the tropics is a well-established physical mechanism for the formation of high clouds that have a positive radiative forcing (even if the possible role of these clouds as a negative climate feedback remains controversial) and (3) even if some cloud properties are not mutually consistent with observations in radiative transfer parameterizations, the most relevant consistency (for the purpose of hypothesis testing) is with observations of the cloud radiative forcing. Therefore, we maintain that cirrus clouds, as observed in the current climate and covering a large region of the tropics, can provide a solution to the faint young sun paradox, or at least ease the amount of CO2 or other greenhouse substances needed to provide temperatures above freezing during the Archean.