bluuebunny/crossref_metadata_2025 huggingface dataset:
Flowing Lattices of Bubbles as Tunable, Self‐Assembled Diffraction Gratings
Authors: Hashimoto Michinao , Mayers Brian , Garstecki Piotr , Whitesides George M.
Published: September 2006

We demonstrate tunable, fluidic, two‐dimensional diffraction gratings based on a microfluidic platform comprising a flow‐focusing bubble generator and flowing, regular lattices of bubbles formed by dynamic self‐assembly. The structure of these lattices can be tuned with switching times of less than ten seconds by changing the pressures and rates of flow applied to the device. These diffraction gratings exhibit high stability (over hours of operation if properly designed and operated). For our devices, we achieved tunable ranges in pitch from 12 to 51 μm, corresponding to first‐order diffraction angles from 3.2° to 0.7° for light with a wavelength of 632 nm.
Adrenal Cysts: An Institutional Experience
Authors: Pradeep P. V. , Mishra Anand K. , Aggarwal Vivek , Bhargav P. R. K. , Gupta Sushil K. , Agarwal Amit
Published: September 2006

Introduction

Adrenal cysts are rare clinical entities. We report our institutional experience with adrenal cysts and also assess various management options.

Material and methods

Over the past 15 years the Department of Endocrine Surgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India, has had seven cases of adrenal cysts, of which two were functional: one patient had Cushing’s syndrome and the other patient had pheochromocytoma. The other five cases were incidentally detected. Ultrasound scan and computerized tomography (CT) scan were the imaging modalities. Four patients had a single cyst, two patients had two cysts, and one patient had multiple unilateral cysts.

Results

None of these cysts had foci of malignancy. Laparoscopic adrenalectomy was possible in three patients with no morbidity or mortality.

Discussion

The reported incidence in clinical series has been 5.4%. Pseudocysts, endothelial cysts, epithelial cysts, and hemorrhagic cysts have been commonly described. The management can be conservative or surgical. It is generally agreed that a hormonal work‐up is necessary in all cases of adrenal cysts to rule out a sub‐clinical disease. Adrenal neoplasms, including adrenocortical carcinomas, can be associated with cysts that are benign in appearance. Percutaneous aspiration has been suggested as an alternative treatment option if the cyst is not hormonally active and if there is no suspicion of malignancy. However, surgical excision provides a definite histopathological diagnosis and also removes the fear of future complications such as hemorrhage into the cyst and local pressure effects due to the tumor.

Conclusions

Given that the adrenals are a vascular gland and taking into consideration the possibilities of bleeding and complications in the cyst, our treatment of choice is the elective excision of adrenal cysts.
Treatment of Abdominal Compartment Syndrome with Subcutaneous Anterior Abdominal Fasciotomy in Severe Acute Pancreatitis
Authors: Leppäniemi Ari K. , Hienonen Piia A. , Siren Jukka E. , Kuitunen Anne H. , Lindström Outi K. , Kemppainen Esko A. J.
Published: September 2006

Background

Managing the abdominal compartment syndrome associated with severe acute pancreatitis by the open abdomen method is associated with considerable morbidity and resource utilization.

Methods

A technique of subcutaneous anterior abdominal fasciotomy is described for the first time in two patients with severe acute pancreatitis.

Results

Following the procedure, the intra‐abdominal pressure decreased from 30 mmHg immediately to 23 mmHg and to a sustained level of 12–14 mmHg in the first patient, and from 35 mmHg immediately to 23 mmHg and to a sustained level of 14–19 mmHg in the second patient.

Conclusions

The subcutaneous anterior abdominal fasciotomy is a promising method for safe and effective abdominal decompression with sustained effect and avoiding the morbidity associated with the alternative open abdomen techniques.
Commercial Mesh versus Nylon Mosquito Net for Hernia Repair. A Randomized Double‐blind Study in Burkina Faso
Authors: Freudenberg Sebastian , Sano Daman , Ouangré Edgar , Weiss Christel , Wilhelm Torsten J.
Published: September 2006

Purpose

The goal of this study was to investigate whether locally available Nylon mosquito net might be a useful alternative to expensive commercial mesh implants for hernia repair, a clinical randomized double‐blind study was performed.

Materials and Methods

Over a period of 3 months 35 patients with a total of 40 inguinal hernias were randomized for hernia repair with either a commercial graft (Ultrapro®) or a piece of sterilized 100% Nylon mesh available as mosquito net in most African village markets. The surgeons’ comfort in handling the meshes, the incidence of complications, and the patients’ quality of life before and 30 days after hernia repair were evaluated. In addition, the costs of the two materials were compared.

Results

There was no significant difference in the clinical short‐term outcome of the hernia treatment or the surgeons’ comfort in handling the two different materials. The price of the locally bought Nylon mesh was 0.0043 US$ as compared to 108 US$ for the commercial mesh.

Conclusions

In situations where superior results of hernia repair depend on the use of a mesh prosthesis but where commercial material is not available or affordable, the use of Nylon mosquito net may be an alternative. Further studies with a larger number of patients and longer follow‐up are justified and recommended.
Role of the Simultaneous Sequential Strategy for Failed Acute Sinus Restoration after Modified Left Maze Procedure for Persistent Atrial Fibrillation with Concomitant Mitral Surgery
Authors: Chang Jen‐Ping , Chen Mien‐Cheng , Kao Chiung‐Lun , Yang Cheng‐Hsu , Yu Teng‐Hung , Chen Chien‐Jen
Published: September 2006

Background

We assessed whether the simultaneous sequential strategy could (1) achieve additional sinus restoration for those patients who were not in sinus rhythm while coming off bypass after modified left maze procedure and (2) attain the same long‐term success rates as the bi‐atrial maze procedure in patients with persistent atrial fibrillation (AF) and mitral valve disease.

Materials and Methods

Twenty‐seven consecutive patients – ten men and 17 women with a mean age of 52 ± 13 years, all with persistent AF and mitral valve disease – underwent the modified maze procedure with the simultaneous sequential strategy. In the first phase, the modified left atrial maze operation was carried out with concomitant valvular surgery; the right side maze operation was subsequently carried out as a second phase of the sequential strategy only if AF re‐appeared following the spontaneous restoration of heart beats during the operation.

Results

Twenty patients (74.1%) underwent the left atrial maze procedure only, and seven patients (25.9%) required the subsequent right atrial maze procedure as part of the sequential strategy. At a mean follow‐up of 15.1 ± 7.7 months, six of the 27 patients (22.2%) who underwent additional right atrial maze procedure had restored sinus rhythm. At a mean follow‐up of 17.8 ± 7.3 months, 24 of the 27 patients (88.9%) had restored sinus rhythm and 22 patients (81.5%) had restored bi‐atrial transport function (right atrial filling fraction: 40.8 ± 11.7%; left atrial filling fraction: 22.9 ± 8.1%) after application of the sequential strategy.

Conclusions

Compared with modified left atrial maze procedure, the application of the simultaneous sequential strategy successfully restored sinus rhythm in an additional 22.2% of patients with persistent AF. The overall sinus conversion rate of 88.9% was comparable with that of the standard bi‐atrial maze procedure.
Religious Involvement and Its Association to Risk Behaviors among Older Youth in Foster Care
Authors: Scott Lionel D. , Munson Michelle R. , McMillen J. Curtis , Ollie Marcia T.
Published: September 2006

This study examined religious involvement and its association to risk behaviors (sexual behavior, marijuana use, alcohol use, and cigarette use) among older youth in foster care (N=383). Three dimensions of religious involvement were assessed—church or religious service attendance, religious practices, and religious beliefs. Findings showed that gender, ethnic group membership, sexual abuse history, and placement type were significantly associated with older foster care youth's religious involvement. Hierarchical logistic regression analyses showed that religious service attendance was associated with reduced odds of youth's engagement in sexual behavior in the past 2 months and current use of cigarettes. In addition, greater religious beliefs were associated with a reduction in odds of youth's use of alcohol in the past 6 months and current use of cigarettes. The consideration of religious involvement as a positive influence and resource that may reduce unhealthy risk behaviors among older youth in foster care is discussed.
Nonarterialized Venous Replantation of Part of Amputated Thumb—A Case Report and Review of the Literature
Authors: Kalimuthu Ramasamy , Herrmann Glenn E.
Published: September 2006

Since the first successful replantation of a human thumb reported by Komatsu and Tamai in 1968, thousands of severed digits and body parts have been successfully salvaged. Restoration of anatomic form and function are the goals of replantation after traumatic tissue amputation. Regardless of anatomic location, methods include microsurgical replantation and nonmicrosurgical replantation, such as composite graft techniques. Numerous techniques to maximize tissue survival after revascularization have been described, including “pocket procedures” to salvage composite grafts, interposition vein grafts, and medicinal leeches to name a few. Artery-to-venous anastomoses have been performed with successful “arterialization” of the distal venous system in fingertip replantation. Although there is documented survival of free venous cutaneous flaps, to our knowledge this is the first report of a replanted composite body part (bone, tendon, soft tissues, and skin) utilizing exclusively multiple, microvascular, nonarterialized venous–venous anastomoses. We present a patient with an isolated band saw fillet amputation to the back of the thumb at the metacarpal–phalangeal joint region, resulting in a composite graft composed of bone, tendon, soft tissue, and skin. The hand wound provided no viable regional arterial inflow source, but there were multiple good caliber superficial veins present. The amputated tissues were replanted and revascularized by using only venous blood flow. The replanted part survival was 100% with excellent function of the digit. We conclude that a hand composite body part involving bone, tendon, soft tissues, and skin can survive replantation with a strict venous blood supply if sufficient good caliber, microvascular, venous–venous anastomoses are performed, granted that arterial inflow options are not available. This is an isolated case, yet introduces a new way of thinking regarding tissue replantation.
Gene–environment interactions in complex diseases: genetic models and methods for QTL mapping in multiple half-sib populations
Authors: KADARMIDEEN HAJA N. , LI YONGJUN , JANSS LUC L. G.
Published: September 2006

An interval quantitative trait locus (QTL) mapping method for complex polygenic diseases (as binary traits) showing QTL by environment interactions (QEI) was developed for outbred populations on a within-family basis. The main objectives, within the above context, were to investigate selection of genetic models and to compare liability or generalized interval mapping (GIM) and linear regression interval mapping (RIM) methods. Two different genetic models were used: one with main QTL and QEI effects (QEI model) and the other with only a main QTL effect (QTL model). Over 30 types of binary disease data as well as six types of continuous data were simulated and analysed by RIM and GIM. Using table values for significance testing, results show that RIM had an increased false detection rate (FDR) for testing interactions which was attributable to scale effects on the binary scale. GIM did not suffer from a high FDR for testing interactions. The use of empirical thresholds, which effectively means higher thresholds for RIM for testing interactions, could repair this increased FDR for RIM, but such empirical thresholds would have to be derived for each case because the amount of FDR depends on the incidence on the binary scale. RIM still suffered from higher biases (15–100% over- or under-estimation of true values) and high standard errors in QTL variance and location estimates than GIM for QEI models. Hence GIM is recommended for disease QTL mapping with QEI. In the presence of QEI, the model including QEI has more power (20–80% increase) to detect the QTL when the average QTL effect is small (in a situation where the model with a main QTL only is not too powerful). Top-down model selection is proposed in which a full test for QEI is conducted first and then the model is subsequently simplified. Methods and results will be applicable to human, plant and animal QTL mapping experiments.
Staphylococcus aureus and Streptococcus dysgalactiae in Norwegian herds after introduction of selective dry cow therapy and teat dipping
Authors: Whist Anne Cathrine , Østerås Olav , Sølverød Liv
Published: September 2006

The objective was to promote a reduction in the prevalence of Staphylococcus aureus and Streptococcus dysgalactiae after 2 years of selective dry cow therapies and teat dipping/external teat sealant implementation. Three different dry cow treatments, one long-acting and two short-acting penicillin-based products were tested at herd level together with a negative control teat dipping group, an iodine teat dipping group and DryFlex™, an external teat sealant. The regimes were independently randomly allocated to 178 dairy herds. Yearly bacteriological quarter milk samples were collected from all cows at the beginning of the trial, after 1 year and 2 years. At herd level, a total of 15% of the herds showed no Staphylococcus aureus isolates after 2 years, compared with 5% at the beginning. The distribution of Streptococcus dysgalactiae infected herds remained the same after 2 years. At cow level, there were no significant differences in the reduction of Staph. aureus between the different dry cow therapies and teat dipping regimes. But there was a significant reduction of Str. dysgalactiae in the iodine teat dipping group compared with Dryflex™ and the negative control group. The proportional rate of Staph. aureus positive quarters was reduced from 65·9% to 54·9% after 2 years. As for Str. dysgalactiae, an increase was observed from 14·2% to 15·2%.
Benthic mapping using local aerial photo interpretation and resident taxa inventories for designing marine protected areas
Authors: ASWANI SHANKAR , LAUER MATTHEW
Published: September 2006

Given the frequent socioeconomic, political and concomitant ecological failures of science-driven marine protected area (MPA) programmes, it is now important to design MPAs by integrating natural and social science research more comprehensively. This study shows how indigenous peoples assisted in the design of MPAs by identifying marine substrates and related resident taxa on aerial photos, information which was then incorporated into a geographical information system (GIS) database, along with dive survey data. Two questions were asked: (1) Is indigenous ecological knowledge accurate enough for mapping the benthos and associated taxa? (2) Is such an approach an appropriate way for assisting in the biological and social design of MPAs in Oceania? Conventional quadrat field dive surveys were used to measure the accuracy of substrate identification by local informants and a visual survey was used to test hypotheses formulated from local knowledge regarding the spatial distribution and relative abundance of non-cryptic species within certain benthic habitats. Equivalence rates between indigenous aerial photo interpretations of dominant benthic substrates and in situ dive surveys were 75–85% for a moderately detailed classification scheme of the benthos, which included nine locally-defined abiotic and biotic benthic classes for the MPA seabed. Similarly, the taxa inventory showed a strong correspondence between the qualitative predictions of local fisherfolk and the quantitative analysis of non-cryptic species distribution, including their relative abundance and geophysical locations. Indigenous people's predictions about the presence or absence of fish in different benthic habitats corresponded 77% and 92% of the time (depending on scoring schema) with in situ visual measurements. These results demonstrate how incorporating local knowledge of benthic heterogeneity, existing biological communities, and particular spatio-temporal events of biological significance into a GIS database can corroborate the production of scientifically reliable base resource maps for designing MPAs in an environmentally and culturally sound fashion. This participatory approach was used to design and then establish MPAs in the Roviana and Vonavona region of the Western Solomon Islands. Under appropriate conditions, interdisciplinary work can complement the design of scientific fishery management and biodiversity conservation prescriptions for coastal Oceania.
Featherweight generic confinement
Authors: POTANIN ALEX , NOBLE JAMES , CLARKE DAVE , BIDDLE ROBERT
Published: September 2006

Existing approaches to object encapsulation either rely on ad hoc syntactic restrictions or require the use of specialised type systems. Syntactic restrictions are difficult to scale and to prove correct, while specialised type systems require extensive changes to programming languages. We demonstrate that confinement can be enforced cheaply in Featherweight Generic Java, with no essential change to the underlying language or type system. This result demonstrates that polymorphic type parameters can simultaneously act as ownership parameters and should facilitate the adoption of confinement and ownership type systems in general-purpose programming languages.
Review of: Methylation of estrogen receptor β promoter correlates with loss of ER-β expression in mammary carcinoma and is an early indication marker in premalignant lesions
Authors: Skliris G. P. , Murphy L. C.
Published: September 2006

Citation of original article:

A. Rody, U. Holtrich, C. Solbach, K. Kourtis, G. von Minckwitz, K. Engels, S. Kissler, R. Gätje, T. Karn, M. Kaufmann. Methylation of estrogen receptor β promoter correlates with loss of ER-β expression in mammary carcinoma and is an early indication marker in premalignant lesions. Endocrine-Related Cancer 2005; 12: 903–916.

Abstract of the original article

The function of estrogen receptor beta (ER-β) in mammary tissue is not completely understood. While early observations were often conflicting, more recent data suggest an important role as a tumor-suppressor gene. A decrease of ER-β expression has been observed in ductal carcinoma in situ and invasive carcinomas as compared with benign mammary epithelial cells. The loss of ER-β resulted in abnormal growth of mammary epithelial cells. We have previously shown that the mRNA expression of the ER-β gene is almost totally suppressed in breast carcinomas from patients with a poor prognosis. Here we analyzed whether methylation changes in the different promoters of ER-β are responsible for the loss of expression of the gene. A methylation assay with high specificity and sensitivity was developed, and a panel of breast tissue samples (n = 175) was characterized for methylation status. In contrast to benign breast, more than two-thirds of invasive breast cancers showed a high degree of methylation. Importantly, increased methylation was also detectable in numerous premalignant lesions. By analysis of breast tumors, previously characterized by gene-expression profiling, methylation was predominantly detected in a subgroup of patients with an unfavorable prognosis, suggesting a possible prognostic value of the ER-β methylation status. We also investigated the structural characteristics of the two ER-β promoters, which were both found to be closely associated with a second, downstream, localized and opposite-oriented promoter. However, we could not detect endogenous antisense RNA transcribed from these promoters, which may be involved in epigenetic gene silencing. We also failed to induce ER-β promoter methylation by expressing siRNAs in cell lines. Interestingly, by comparing the promoter sequences of ER-β with other genes known to be epigenetically inactivated in breast cancers, we identified a sequence motif possibly involved in promoter methylation.
Cell‐Free Protein Synthesis System Prepared from Insect Cells by Freeze‐Thawing
Authors: Ezure Toru , Suzuki Takashi , Higashide Shoken , Shintani Eiichi , Endo Kohki , Kobayashi Shin‐ichiro , Shikata Masamitsu , Ito Masaaki , Tanimizu Koji , Nishimura Osamu
Published: September 2006

We established a novel cell‐free protein synthesis system derived from Trichoplusia ni (HighFive) insect cells by a simple extraction method. Luciferase and β‐galactosidase were synthesized in this system with active forms. We analyzed and optimized (1) the preparation method of the insect cell extract, (2) the concentration of the reaction components, and (3) the 5′‐untranslated region (5′‐UTR) of mRNA. The extract was prepared by freeze‐thawing insect cells suspended in the extraction buffer. This preparation method was a simple and superior method compared with the conventional method using a Dounce homogenizer. Furthermore, protein synthesis efficiency was improved by the addition of 20% (v/v) glycerol to the extraction buffer. Concentrations of the reaction components were optimized to increase protein synthesis efficiency. Moreover, mRNAs containing 5′‐UTRs derived from baculovirus polyhedrin genes showed high protein synthesis activity. Especially, the leader composition of the Ectropis obliqua nucleopolyhedrovirus polyhedrin gene showed the highest enhancement activity among the six 5′‐UTRs tested. As a result, in a batch reaction approximately 71 μg of luciferase was synthesized per milliliter of reaction volume at 25 °C for 6 h. Moreover, this method for the establishment of a cell‐free system was applied also to Spodoptera frugiperda 21 (Sf21) insect cells. After optimizing the concentrations of the reaction components and the 5′‐UTR of mRNA, approximately 45 μg/mL of luciferase was synthesized in an Sf21 cell‐free system at 25 °C for 3 h. These productivities were sufficient to perform gene expression analyses. Thus, these cell‐free systems may be a useful tool for simple synthesis in post‐genomic studies as a novel protein production method.
A simple model of the Arctic Ocean response to annular atmospheric modes
Authors: Newton Bob , Tremblay L. Bruno , Cane Mark A. , Schlosser Peter
Published: September 2006

A dynamical mechanism is described that modulates the tilt of the sea‐surface height and pycnocline depth between the central Arctic and the continental shelves. A simple analytical model is presented, forced with idealized zonal winds over an idealized, 2‐layer, cylinder representing the Arctic Ocean. Ekman transports are linked to sea‐surface and pycnocline tilt anomalies and basin‐scale circulation in response to an annular wind anomaly. We compare the results to tide gauge data, as well as results from a more realistic numerical simulation and find that the model explains a major fraction of the interannual‐to‐decade scale sea‐surface height anomalies at Arctic coastal tide gauges. The analytical model indicates, for example, that on the order of 10 cm of the observed rise of about 18 cm in coastal Arctic sea‐surface height between about 1985 and 1993 was probably a response to increased Westerly winds associated with a strong positive phase of the Northern Annular Mode of atmospheric variability. The pycnocline depth anomaly time series from the model is used to calculate implied changes in the outflow of relatively fresh Polar Water to the North Atlantic. The comparisons indicate that the Ekman transport mechanism is important to changes in the export of buoyancy from the Arctic Ocean on seasonal, interannual, and decadal timescales.
Nightside thermospheric FUV emissions due to energetic neutral atom precipitation during magnetic superstorms
Authors: Zhang Y. , Paxton L. J. , Kozyra J. U. , Kil H. , Brandt P. C.
Published: September 2006

TIMED/GUVI detected anomalous FUV emissions from the nightside thermosphere over a wide latitude range, from the subauroral latitudes to the equatorial regions during each of three magnetic superstorms (29–31 October 2003, 20 November 2003, and 7–10 November 2004). We note that during the one case (7–10 November 2004) where there were coincident measurements of the flux of energetic particles as observed by IMAGE HENA, the FUV intensity (as seen in five bandpasses or “colors”: 121.6 nm, 130.4 nm, 135.6 nm, LBHS (140–150 nm) and LBHL (165–180 nm)) showed qualitative agreement with the behavior of the energetic neutral atoms (ENA). This suggests that the source of the FUV emissions is the ENA originating from the ring current. We also found that for all three storms we studied that the FUV intensities are well correlated with Dst. The intensity in all colors is observed to increase with latitude up to the auroral oval. Except for 121.6 nm, the observed intensities exhibit a sharp decrease near the magnetic equator region. The origin, location, and spatial extent of the FUV emissions is quite different from that of the traditional aurora, we find that this phenomena is consistent with neutral particle precipitation. We call this signature of the coupling of the ring current and the thermosphere the neutral particle aurora.
Dependence of neutral winds on convection E‐field, solar EUV, and auroral particle precipitation at high latitudes
Authors: Deng Y. , Ridley A. J.
Published: September 2006

We use the Global Ionosphere Thermosphere Model (GITM) to investigate the thermospheric neutral winds and their relationship to the high‐latitude ionospheric convection, auroral precipitation, and solar activity. Each simulation is run for 24 hours, allowing an approximate steady state to be reached. Our results show that the duskside vortex and the antisunward polar cap neutral winds are prominent. The interplanetary magnetic field (IMF) southward Bz control of the polar cap winds is evident in both dusk cell and polar cap. When the IMF Bz changes from −1 to −10 nT, at the auroral region both the root of mean square (RMS) of Vn and Vi increase more than 50% at 300 km altitude, the ratio of R2 (RMS(Vn · (E × B))/RMS(E × B)2) increases, while R1 (RMS(Vn)/RMS(E × B)) changes little. In the polar cap region, since the ion flow is in the same direction as the neutral pressure gradient, above around 160 km altitude, ∣Vn∣ is larger than ∣Vi∣. When the F10.7 increases from 70 to 250, in the auroral region, the magnitude of ∣Vn∣ increases close to 20% at 300 km altitude. At lower latitudes, where ∣Vn∣ > ∣Vi∣ and the ions act as a load to the neutral winds, as a consequence of increases in F10.7, the drag on the neutrals becomes greater and therefore slows the neutrals down. The altitude dependent change of R2 is associated with the multiple effects of the F10.7 to the neutral winds, including the increased day‐to‐night pressure gradient and ion drag. The impact of hemispheric power (HP) to the low thermosphere is pronounced. At 150 km altitude, the neutral winds increase 30% in magnitude at auroral latitudes. When HP is raised from 10 to 100 GW, a dawn cell forms, concurrent with an enhancement in the dusk cell. The dawn and dusk cells show an obvious asymmetry both in the average neutral winds and the sensitivity of neutral winds to the HP. It is shown that at 250 km altitude, the magnitude of the southward IMF Bz has a positive correlation with the magnitude of the polar cap winds and the sensitivity increases with F10.7. A negative correlation between the magnitude of Vn and F10.7 with small southward IMF Bz becomes positive when the southward IMF Bz increases. This change is presumably due to the momentum balance between ion drag and advection. The dawn (dusk) convection cell is enhanced when By is negative (positive). In response to the effect of the Coriolis force, the By negative winds are not exactly mirror reflections of the By positive winds. For northward IMF Bz, the neutral winds flow sunward at the highest latitudes near noon. When the northward Bz increases from 10 nT to 20 nT, the distribution of the polar cap potential becomes more symmetric and the sunward neutral flow is enhanced and expanded.
Troposphere‐thermosphere tidal coupling as measured by the SABER instrument on TIMED during July–September 2002
Authors: Forbes J. M. , Russell J. , Miyahara S. , Zhang X. , Palo S. , Mlynczak M. , Mertens C. J. , Hagan M. E.
Published: September 2006

Coupling between the troposphere and lower thermosphere due to upward propagating tides is investigated using temperatures measured from the SABER instrument on the TIMED satellite. The data analyzed here are confined to 20–120 km altitude and ±40° latitude during 20 July to 20 September 2002. Apart from the migrating (Sun‐synchronous) tidal components, the predominant feature seen (from the satellite frame) during this period is a wave‐4 structure in longitude with extrema of up to ±40–50 K at 110 km. Amplitudes and longitudes of maxima of this structure evolve as the satellite precesses in local time and as the wave(s) responsible for this structure vary with time. The primary wave responsible for the wave‐4 pattern is the eastward propagating diurnal tide with zonal wave number s = 3 (DE3). Its average amplitude distribution over the interval is quasi‐symmetric about the equator, similar to that of a Kelvin wave, with maximum of about 20 K at 5°S and 110 km. DE3 is primarily excited by latent heating due to deep tropical convection in the troposphere. It is demonstrated that existence of DE3 is intimately connected with the predominant wave‐4 longitude distribution of topography and land‐sea difference at low latitudes, and an analogy is drawn with the strong presence of DE1 in Mars atmosphere, the predominant wave‐2 topography on Mars, and the wave‐2 patterns that dominate density measurements from the Mars Global Surveyor (MGS) spacecraft near 130 km. Additional diurnal, semidiurnal, and terdiurnal nonmigrating tides are also revealed in the present study. These tidal components are most likely excited by nonlinear interactions between their migrating counterparts and the stationary planetary wave with s = 1 known to exist in the Southern Hemisphere during this period just prior to the austral midwinter stratospheric warming of 2002.
Coupling effects throughout the solar atmosphere: 2. Model of energetically open circuit
Authors: Ryutova M.
Published: September 2006

EUV structures in the solar atmosphere are studied on the basis of the energetically open equivalent circuits. The systems consist of current carrying magnetic loops that interconnect a high β energy‐production region with a low β dissipation region and include the transition region where the most efficient generation of currents and transport of the accumulated energy through the resistive stresses occurs. As nonconservative systems with a source and sink of energy, they may be driven into various dynamic forms via nonlinear processes with continuous flow of matter and energy. The corresponding equivalent circuit equation has the form of the Van der Pol oscillator. Depending on the coefficients determined by the system parameters, this equation describes different behaviors of the EUV structures including long‐living steady loops with subtle oscillations, loops in the relaxation regime, and the periodically flaring and exploding loop systems. The model predicts that the EUV loops must have a filamentary structure and allows us to estimate the limiting currents and critical radii of elemental filaments associated with the stability criteria. Simple relations between the parameters, most of which are observables, may provide reliable diagnostic tools.
Effect of changing Southern Hemisphere winter sea surface temperatures on Southern Annular Mode strength
Authors: Marshall Gareth J. , Connolley William M.
Published: September 2006

We examine the impact that changes in the winter Southern Hemisphere (SH) meridional sea surface temperature (SST) gradient have on the sign and strength of the SH Annular Mode (SAM). This is undertaken by perturbing either tropical or extra‐tropical SSTs in an atmospheric General Circulation Model. Changes in winter tropical SSTs have little direct influence on the SAM but do force a strong wave train in geopotential height across the Southern Ocean. In contrast, changes in winter SSTs in the SH extra‐tropics have a profound effect on the SAM: cooler SSTs strengthen the SAM and vice versa. The mechanism involves modifications to the Ferrel cell. As a positive (negative) SAM enhances (reduces) the extra‐tropical meridional temperature gradient, these experiments demonstrate a positive feedback mechanism. SAM variability remains unchanged, indicating a shift in the mean, rather than a change in the probability distribution of its positive and negative phases.
Cloud type climatology over the Tibetan Plateau: A comparison of ISCCP and MODIS/TERRA measurements with surface observations
Authors: Li Yueqing , Liu Xiaodong , Chen Baode
Published: September 2006

Area averaged seasonal climatology of high, middle and low clouds over the Tibetan Plateau was obtained from the International Satellite Cloud Climatology Project (ISCCP) D2 and the Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra products, and was compared with climatology calculated by using the Carbon Dioxide Information Analysis Center (CDIAC) Cloud Climatology for Land Station Worldwide. From all three data sets, there is a large degree of consistency for the high cloud climatology in terms of amount and occurrence frequency. A great amount of high clouds exists over the Tibetan Plateau and its seasonal cycle is evident with the largest amount and highest frequency in spring and summer. However, compared with the surface observations, both the ISCCP D2 and the MODIS/Terra products largely underestimated low clouds over the Tibetan Plateau. Approximately, the underestimation of cloud amount from the ISCCP D2 is more than 20% and cloud frequency bias from the MODIS/Terra up to 50%; moreover, a quite large discrepancy in the seasonal cycle is shown. For middle clouds, the ISCCP D2 and the MODIS/Terra products overestimate amount and occurrence frequency, and present rather weak seasonal variation compared with the weather station data. When using satellite data to analyze cloud cover the Tibetan Plateau, certain issues about large potential bias must be taken into consideration, and particularly, great caution is needed while using the ISCCP D2 and MODIS data to study middle and low clouds, especially when high and thick clouds exist.
CO2 and CH4 exchanges between land ecosystems and the atmosphere in northern high latitudes over the 21st century
Authors: Zhuang Qianlai , Melillo Jerry M. , Sarofim Marcus C. , Kicklighter David W. , McGuire A. David , Felzer Benjamin S. , Sokolov Andrei , Prinn Ronald G. , Steudler Paul A. , Hu Shaomin
Published: September 2006

Terrestrial ecosystems of the northern high latitudes (above 50°N) exchange large amounts of CO2 and CH4 with the atmosphere each year. Here we use a process‐based model to estimate the budget of CO2 and CH4 of the region for current climate conditions and for future scenarios by considering effects of permafrost dynamics, CO2 fertilization of photosynthesis and fire. We find that currently the region is a net source of carbon to the atmosphere at 276 Tg C yr‐1. We project that throughout the 21st century, the region will most likely continue as a net source of carbon and the source will increase by up to 473 Tg C yr−1 by the end of the century compared to the current emissions. However our coupled carbon and climate model simulations show that these emissions will exert relatively small radiative forcing on global climate system compared to large amounts of anthropogenic emissions.
An empirical rule for extended range prediction of duration of Indian summer monsoon breaks
Authors: Dwivedi Suneet , Mittal Ashok Kumar , Goswami B. N.
Published: September 2006

Prediction of the duration of the Indian summer monsoon breaks is highly desirable. It will help in planning water resource management, sowing and harvesting. Applicability of the recently discovered regime transition rules for the Lorenz model in predicting the duration of monsoon breaks, is explored in this paper. Using several indices of the observed summer monsoon intraseasonal oscillation (ISO), it is shown that the peak anomaly in an active regime can be used as a predictor for the duration of the subsequent break spell. It is also found that the average growth rate around the threshold to an active condition can be used as a predictor of the peak anomaly in the active spell. Average growth around the threshold to an active condition can give useful prediction of the duration of the following break, on an average, about 23 days (38 days) in advance of its commencement (end).
Interpreting the complementary relationship in non‐humid environments based on the Budyko and Penman hypotheses
Authors: Yang Dawen , Sun Fubao , Liu Zhiyu , Cong Zhentao , Lei Zhidong
Published: September 2006

The Budyko, Bouchet, and Penman hypotheses together describe, using different formulae, the tight connections and feedbacks between water–energy balances and the landscape. The discrepancy between the Penman and Bouchet hypotheses is usually highlighted in non‐humid regions. In this paper, using Fu's equation for annual water‐energy balances at the catchment scale, which was derived phenomenologically and mathematically on the basis of the Budyko hypothesis, consistency among the three hypotheses is explained. In non‐humid regions, change of actual evaporation is dominated by change in precipitation rather than potential evaporation, and the Bouchet complementary relationship between actual evaporation and potential evaporation comes about because actual evaporation and potential evaporation are correlated via precipitation. The annual water balances in 108 non‐humid catchments of China have been examined as part of this study, and the results supported the complementary relationship. In humid regions, change in actual evaporation is controlled by change in potential evaporation rather than precipitation, and this is identical to the Penman hypothesis.
Self‐consistent formation of electron κ distribution: 2. Further numerical investigation
Authors: Rhee Tongnyeol , Ryu Chang‐Mo , Yoon Peter H.
Published: September 2006

In the preceding article (Yoon et al., 2006) the basic physics behind the generation of suprathermal electrons (the κ distribution) by means of self‐consistent processes is elucidated. In this followup paper, further numerical investigation of the electron κ formation is carried out. In particular, the underlying input physical parameters which include the plasma parameter g = 1/λD3, the electron beam‐to‐background density ratio, b/, the electron‐to‐ion temperature ratio, Te/Ti, and the ratio of average beam speed to electron thermal speed, V0/vTe, are systematically varied. It is shown that the electron suprathermal tail formation takes place over a wide range of physical parameters. It is also found that the formation of suprathermal tail appears to exhibit critical behavior in that there is a threshold beam energy below which no suprathermal population is formed, but when the energy threshold is crossed, the tail generation is greatly facilitated.
Zonal variations of peak ionization rates in upper atmosphere of Mars at high latitude using Mars Global Surveyor accelerometer data
Authors: Seth S. P. , Brahmananda Rao V. , Esprito Santo C. M. , Haider S. A. , Choksi V. R.
Published: September 2006

The Accelerometer Experiment onboard Mars Global Surveyor (MGS) measured many density profiles in the upper atmosphere of Mars during aerobraking at many latitudes, longitudes, altitudes, local solar time (LST), and seasons. Here, in this paper, we use the accelerometer data of 57 orbits (P0588–P0648) from 30 September 1998 to 24 October 1998 between latitude ranges (50°–70°N) at LST 1600 hours, under spring equinox and medium solar activity conditions (average F10.7 ∼ 120). Using these densities, the neutral densities of different gases are derived from their mixing ratio. From these neutral densities the longitudinal distribution of peak photoionization rates, peak photoelectron impact ionization rates, and the total peak ionization rates of CO2+, N2+ and O+ are obtained for solar zenith angle 78° at wavelength range 10–1025.7 Å due to solar EUV radiation using analytical yield spectrum approach (AYS). These calculations are made at different altitudes and longitudes starting from 115 to 220 km and 0° to 360°E using intervals of 0.1 km and 5°, respectively. These conditions are appropriate for MGS phase 2 aerobraking period from which the accelerometer data are used. The Fourier analysis of the various peak ionization rates of CO2+, N2+, and O+ indicates the presence of two dominant harmonic regions at high latitude in the upper atmosphere of Mars. The first is a class of long planetary‐scale waves that may be associated with the fixed topography of Martian surface. The second is a class of rapidly moving transient disturbances that may be associated with baroclinic instability processes.
SPICAM IR acousto‐optic spectrometer experiment on Mars Express
Authors: Korablev Oleg , Bertaux Jean‐Loup , Fedorova Anna , Fonteyn D. , Stepanov A. , Kalinnikov Y. , Kiselev A. , Grigoriev A. , Jegoulev V. , Perrier S. , Dimarellis E. , Dubois J. P. , Reberac A. , Van Ransbeeck E. , Gondet B. , Montmessin F. , Rodin A.
Published: September 2006

The SPICAM IR spectrometer on Mars Express mission (1.0–1.7 μm, spectral resolution 0.5–1.2 nm) is dedicated primarily to nadir measurements of H2O abundance. It is one of two channels of SPICAM UV‐IR instrument. In this spectrometer we applied for the first time in planetary research the technology of an acousto‐optic tunable filter (AOTF) that allowed unprecedented mass reduction for such an instrument: 0.75 kg. SPICAM IR is a point nadir‐looking spectrometer with sequential scanning of the spectrum by the AOTF. Sun occultations are performed with a help of dedicated solar port. We describe instrumentation, calibrations, and the modes of operations of the device and discuss its in‐flight performances. A brief overview of the scientific measurements includes water vapor measurements and the mapping of intensity of the O2(a1Δg) emission at 1.27 μm, described in detail in separate papers. Measurements in reflected solar light allow clear detection of H2O and CO2 ices on the surface or in the atmosphere of Mars. We discuss solar occultation measurements by SPICAM and present resulting vertical profiles of aerosol optical depth.
Nature and stability of the (100)Si∕LaAlO3 interface probed by paramagnetic defects
Authors: Stesmans A. , Clémer K. , Afanas’ev V. V. , Edge L. F. , Schlom D. G.
Published: September 2006

Electron spin resonance analysis of (100)Si∕LaAlO3 structures reveals the absence of a Si∕SiO2-type interface in terms of archetypal Si-dangling bond-type Si∕SiO2 interface defects (Pb0,Pb1). With no Pb-type defects observed, this state is found to persist during subsequent annealing (5% O2+N2 ambient) up to Tan∼800°C, indicating a thermally stable and abrupt Si∕LaAlO3 interface. In the range Tan∼800–860°C, however, a Si∕SiO2-type interface starts forming as evidenced by the appearance of Pb0 defects and, with some delay in Tan, the EX center (a SiO2 associated defect) attesting to significant structural/compositional modification. The peaking of the defect density versus Tan curves indicates that the interlayer with SiOx nature breaks up upon annealing at Tan⩾930°C, possibly related to crystallization and silicate formation. No LaAlO3-specific point defects could be detected.
Direct simulations of flexible cylindrical fiber suspensions in finite Reynolds number flows
Authors: Qi Dewei
Published: September 2006

Direct simulations of flexible cylindrical fiber suspensions in a finite Reynolds number flow are reported. The simulation method is based on a lattice Boltzmann equation and a flexible fiber model. A slender solid body is discretized into a chain of cylindrical segments contacting each other at the their ends through ball and socket joints that allow adjacent segments to rotate around the joints in three dimensional space. A constraint force is imposed at each joint. In general, motion and rotational matrices of each segment are functions of constraint forces. It is necessary to linearize the rotational matrices in forces and torques so that constraint forces could be solved using joint contacting conditions. Therefore, quaternion parameters as well as rotational matrix could be expanded in a power series of the length of time step up to a second order. A half leapfrog algorithm D. Fincham, [CCP5 Quarterly, 2, 6 (1981)] is modified to ensure the ball and socket joint conditions to be satisfied at each time step. The validation of the present flexible fiber method is tested by using a rigid particle method. It is shown that the computational results are consistent with the existing experimental and theoretical results at finite Reynolds number flows. With the present method, nonlinear inertial interactions between fluid and flexible filaments can be naturally studied. A few applications are included.
Sheaf-theoretic representation of quantum measure algebras
Authors: Zafiris Elias
Published: September 2006

We construct a sheaf-theoretic representation of quantum probabilistic structures, in terms of covering systems of Boolean measure algebras. These systems coordinatize quantum states by means of Boolean coefficients, interpreted as Boolean localization measures. The representation is based on the existence of a pair of adjoint functors between the category of presheaves of Boolean measure algebras and the category of quantum measure algebras. The sheaf-theoretic semantic transition of quantum structures shifts their physical significance from the orthoposet axiomatization at the level of events, to the sheaf-theoretic gluing conditions at the level of Boolean localization systems.
On the optimality of quantum encryption schemes
Authors: Nagaj Daniel , Kerenidis Iordanis
Published: September 2006

It is well known that n bits of entropy are necessary and sufficient to perfectly encrypt n bits (one-time pad). Even if we allow the encryption to be approximate, the amount of entropy needed does not asymptotically change. However, this is not the case when we are encrypting quantum bits. For the perfect encryption of n quantum bits, 2n bits of entropy are necessary and sufficient (quantum one-time pad), but for approximate encryption one asymptotically needs only n bits of entropy. In this paper, we provide the optimal trade-off between the approximation measure ϵ and the amount of classical entropy used in the encryption of single quantum bits. Then, we consider n-qubit encryption schemes which are a composition of independent single-qubit ones and provide the optimal schemes both in the 2- and the ∞-norm. Moreover, we provide a counterexample to show that the encryption scheme of Ambainis-Smith [Proceedings of RANDOM ’04, pp. 249–260] based on small-bias sets does not work in the ∞-norm.