bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Idealized Heterogeneity on Wet and Dry Planetary Boundary Layers Coupled to the Land Surface
Authors: Patton Edward G. , Sullivan Peter P. , Moeng Chin-Hoh
Published: August 2005

This manuscript describes numerical experiments investigating the influence of 2–30-km striplike heterogeneity on wet and dry convective boundary layers coupled to the land surface. The striplike heterogeneity is shown to dramatically alter the structure of the convective boundary layer by inducing significant organized circulations that modify turbulent statistics. The impact, strength, and extent of the organized motions depend critically on the scale of the heterogeneity λ relative to the boundary layer height zi. The coupling with the land surface modifies the surface fluxes and hence the circulations resulting in some differences compared to previous studies using fixed surface forcing. Because of the coupling, surface fluxes in the middle of the patches are small compared to the patch edges. At large heterogeneity scales (λ/zi ∼18) horizontal surface-flux gradients within each patch are strong enough to counter the surface-flux gradients between wet and dry patches allowing the formation of small cells within the patch coexisting with the large-scale patch-induced circulations. The strongest patch-induced motions occur in cases with 4 < λ/zi < 9 because of strong horizontal pressure gradients across the wet and dry patches. Total boundary layer turbulence kinetic energy increases significantly for surface heterogeneity at scales between λ/zi = 4 and 9; however, entrainment rates for all cases are largely unaffected by the striplike heterogeneity.

Velocity and scalar fields respond differently to variations of heterogeneity scale. The patch-induced motions have little influence on total vertical scalar flux, but the relative contribution to the flux from organized motions compared to background turbulence varies with heterogeneity scale. Patch-induced motions are shown to dramatically impact point measurements in a free-convective boundary layer. The magnitude and sign of this impact depends on the location of the measurement within the region of heterogeneity.
Linking Nonlinearity and Non-Gaussianity of Planetary Wave Behavior by the Fokker–Planck Equation
Authors: Berner Judith
Published: August 2005

To link prominent nonlinearities in the dynamics of 500-hPa geopotential heights to non-Gaussian features in their probability density, a nonlinear stochastic model of atmospheric planetary wave behavior is developed. An analysis of geopotential heights generated by extended integrations of a GCM suggests that a stochastic model and its associated Fokker–Planck equation call for a nonlinear drift and multiplicative noise. All calculations are carried out in the reduced phase space spanned by the leading EOFs. It is demonstrated that this nonlinear stochastic model of planetary wave behavior captures the non-Gaussian features in the probability density function of atmospheric states to a remarkable degree. Moreover, it not only predicts global temporal characteristics, but also the nonlinear, state-dependent divergence of state trajectories. In the context of this empirical modeling, it is discussed on which time scale a stochastic model is expected to approximate the behavior of a continuous deterministic process.

The reduced model is then used to determine the importance of the nonlinearities in the drift and the role of the multiplicative noise. While the nonlinearities in the drift are crucial for a good representation of planetary wave behavior, multiplicative (i.e., state dependent) noise is not absolutely essential. It is found that a major contributor to the stochastic component is the Branstator–Kushnir oscillation, which acts as a fluctuating force for physical processes with even longer time scales, like those that project on the Arctic Oscillation pattern. In this model, the oscillation is represented by strongly correlated noise.
Where is the Interface of the Stratocumulus-Topped PBL?
Authors: Moeng C-H. , Stevens B. , Sullivan P. P.
Published: August 2005

Various locally defined (not horizontal mean) interfaces between the stratocumulus-topped PBL and the free atmosphere are investigated using a fine-resolution large-eddy simulation with a vertical grid spacing of about 4 m. The local cloud-top height is found to be always below the height where the maximum gradient of the local sounding occurs, and the maximum-gradient height is always below the interface where PBL air can reach via turbulent motions. The distances between these local interfaces are of significant amount, a few tens of meters on average. Air between the cloud-top and maximum-gradient interfaces is fully turbulent, unsaturated, but rather moist. Air between the maximum-gradient and turbulent-mixing interfaces consists of turbulent motions that are intermittent in space and time. The simulated flow shows no clearly defined interface that separates cloudy, turbulent air mass from clear, nonturbulent air above, even locally.
Nonlocal Convective PBL Model Based on New Third- and Fourth-Order Moments
Authors: Cheng Y. , Canuto V. M. , Howard A. M.
Published: August 2005

The standard approach to studying the planetary boundary layer (PBL) via turbulence models begins with the first-moment equations for temperature, moisture, and mean velocity. These equations entail second-order moments that are solutions of dynamic equations, which in turn entail third-order moments, and so on. How and where to terminate (close) the moments equations has not been a generally agreed upon procedure and a variety of models differ precisely in the way they terminate the sequence. This can be viewed as a bottom-up approach. In this paper, a top-down procedure is suggested, worked out, and justified, in which a new closure model is proposed for the fourth-order moments (FOMs). The key reason for this consideration is the availability of new aircraft data that provide for the first time the z profile of several FOMs. The new FOM expressions have nonzero cumulants that the model relates to the z integrals of the third-order moments (TOMs), giving rise to a nonlocal model for the FOMs. The new FOM model is based on an analysis of the TOM equations with the aid of large-eddy simulation (LES) data, and is verified by comparison with the aircraft data. Use of the new FOMs in the equations for the TOMs yields a new TOM model, in which the TOMs are damped more realistically than in previous models. Surprisingly, the new FOMs with nonzero cumulants simplify, rather than complicate, the TOM model as compared with the quasi-normal (QN) approximation, since the resulting analytic expressions for the TOMs are considerably simpler than those of previous models and are free of algebraic singularities. The new TOMs are employed in a second-order moment (SOM) model, a numerical simulation of a convective PBL is run, and the resulting mean potential temperature T, the SOMs, and the TOMs are compared with several LES data. As a final consistency check, T, SOMs, and TOMs are substituted from the PBL run back into the FOMs, which are again compared with the aircraft data.
Radiative Impacts on the Growth of Drops within Simulated Marine Stratocumulus. Part I: Maximum Solar Heating
Authors: Hartman Christopher M. , Harrington Jerry Y.
Published: August 2005

The effects of solar heating and infrared cooling on the vapor depositional growth of cloud drops, and hence the potential for collection enhancement, is investigated. Large eddy simulation (LES) of marine stratocumulus is used to generate 600 parcel trajectories that follow the mean motions of the cloud. Thermodynamic, dynamic, and radiative cloud properties are stored for each trajectory. An offline trajectory ensemble model (TEM) coupled to a bin microphysical model that includes the influences of radiation on drop growth is driven by the 600-parcel dataset.

In line with previous results, including infrared cooling causes a reduction in the time for collection onset. This collection enhancement increases with drop concentration. Larger concentrations (400 cm−3) show a reduction in collection onset time of as much as 45 min. Including infrared cooling as well as solar heating in the LES and microphysical bin models has a number of effects on the growth of cloud drops. First, shortwave (SW) heating partially offsets cloud-top longwave (LW) cooling, which naturally reduces the influence of LW cooling on drop growth. Second, SW heating dominates over LW cooling at larger drop radii (≳200 μm), which causes moderately sized drops to evaporate. Third, unlike LW cooling, SW heating occurs throughout the cloud deck, which suppresses drop growth. All three of these effects tend to narrow the drop size spectrum. For intermediate drop concentrations (100–200 cm−3), it is shown that SW heating primarily suppresses collection initiation whereas at larger drop concentrations (≳250 cm−3) LW cooling dominates causing enhancements in collection.
Radiative Impacts on the Growth of Drops within Simulated Marine Stratocumulus. Part II: Solar Zenith Angle Variations
Authors: Hartman Christopher M. , Harrington Jerry Y.
Published: August 2005

The effects of solar heating at a variety of solar zenith angles (Θo) on the vapor depositional growth of cloud drops, and hence the potential for collection enhancement, is investigated. A large eddy simulation (LES) model is used to predict the evolution of marine stratocumulus clouds subject to changes in Θo. During the course of each simulation, LES output is stored for 600 parcel trajectories and is used to drive an offline microphysical model that includes the influence of radiation on drop growth.

Smaller Θo, such as when the sun is overhead, provide strong solar heating, which tends to confine circulations to the cloud layer and leads to long in-cloud residence times for cloud drops. At larger Θo, when solar heating is weak, circulations are stronger and penetrate through the depth of the boundary layer, which causes much shorter in-cloud residence times for cloud drops. Simulations show that this leads to a more rapid collection process in strongly, as compared to weakly solar-heated clouds provided that the liquid water contents of each cloud are similar. When drop vapor growth includes radiative effects, three main results emerge: 1) Solar heating at smaller Θo (0° to 45°) dominates over longwave cooling effects causing a suppression of collection for lower drop concentrations (100 to 200 cm−3). 2) At larger drop concentrations (≳300 cm−3) longwave cooling dominates over solar heating and collection is enhanced. 3) At large Θo (60° to 90°), solar heating is ineffective at modifying the drop size spectrum thus allowing longwave cooling to significantly enhance collection at all drop concentrations above approximately 100 cm−3.
The GCM Response to Current Parameterizations of Nonorographic Gravity Wave Drag
Authors: McLandress Charles , Scinocca John F.
Published: August 2005

A comparison is undertaken of the response of a general circulation model (GCM) to the nonorographic gravity wave drag parameterizations of Hines, Warner and McIntyre, and Alexander and Dunkerton. The analysis is restricted to a comparison of each parameterization’s nonlinear dissipation mechanism since, in principle, this is the only component that differs between the schemes. This is achieved by developing a new, more general parameterization that can represent each of these dissipation mechanisms, while keeping all other aspects of the problem identical.

The GCM simulations reveal differences in the climatological response to the three dissipation mechanisms. These differences are documented for both tropopause and surface launch elevations of the parameterized waves. The simulations also reveal systematic differences in the height at which momentum is deposited. This behavior is investigated further in a set of experiments designed to reduce these systematic differences, while leaving the details of the dissipation mechanisms unaltered. These sensitivity experiments demonstrate that it is possible to obtain nearly identical responses from all three mechanisms, which indicates that the GCM response is largely insensitive to the precise details of the dissipation mechanisms. This finding is supported by an additional experiment in which the nonlinear dissipation mechanisms are turned off and critical-level filtering is left to act as the only source of dissipation. In this experiment, critical-level filtering effectively replaces the nonlinear dissipation mechanism, producing a nearly identical response.

The results of this study suggest that climate modeling efforts would potentially benefit more from the refinement of other aspects of the parameterization problem, such as the properties of the launch spectrum, than they have benefited from the refinement of dissipation mechanisms.
The Origin of High Ice Crystal Number Densities in Cirrus Clouds
Authors: Hoyle C. R. , Luo B. P. , Peter T.
Published: August 2005

Recent measurements with four independent particle instruments in cirrus clouds, which formed without convective or orographic influence, report high number densities of ice particles (as high as nice = 50 cm−3) embedded in broad density distributions (nice = 0.1–50 cm−3). It is shown here that small-scale temperature fluctuations related to gravity waves, mechanical turbulence, or other small-scale air motions are required to explain these observations. These waves have typical peak-to-peak amplitudes of 1–2 K and frequencies of up to 10 h−1, corresponding to instantaneous cooling rates of up to 60 K h−1. Such waves remain unresolved in even the most advanced state-of-the-art global atmospheric models. Given the ubiquitous nature of these fluctuations, it is suggested that the character of young in situ forming cirrus clouds is mostly determined by homogeneous freezing of ice in solution droplets, driven by a broad range of small-scale fluctuations (period ∼a few minutes) with moderate to high cooling rates (1–100 K h−1).
The Tropical Convective Spectrum. Part I: Archetypal Vertical Structures
Authors: Boccippio Dennis J. , Petersen Walter A. , Cecil Daniel J.
Published: August 2005

A taxonomy of tropical convective and stratiform vertical structures is constructed through cluster analysis of 3 yr of Tropical Rainfall Measuring Mission (TRMM) “warm-season” (surface temperature greater than 10°C) precipitation radar (PR) vertical profiles, their surface rainfall, and associated radar-based classifiers (convective/stratiform and brightband existence). Twenty-five archetypal profile types are identified, including nine convective types, eight stratiform types, two mixed types, and six anvil/fragment types (nonprecipitating anvils and sheared deep convective profiles). These profile types are then hierarchically clustered into 10 similar families, which can be further combined, providing an objective and physical reduction of the highly multivariate PR data space that retains vertical structure information. The taxonomy allows for description of any storm or local convective spectrum by the profile types or families. The analysis provides a quasi-independent corroboration of the TRMM 2A23 convective/stratiform classification. The global frequency of occurrence and contribution to rainfall for the profile types are presented, demonstrating primary rainfall contribution by midlevel glaciated convection (27%) and similar depth decaying/stratiform stages (28%–31%). Profiles of these types exhibit similar 37- and 85-GHz passive microwave brightness temperatures but differ greatly in their frequency of occurrence and mean rain rates, underscoring the importance to passive microwave rain retrieval of convective/stratiform discrimination by other means, such as polarization or texture techniques, or incorporation of lightning observations. Close correspondence is found between deep convective profile frequency and annualized lightning production, and pixel-level lightning occurrence likelihood directly tracks the estimated mean ice water path within profile types.
Impacts of the Aleutian–Icelandic Low Seesaw on Surface Climate during the Twentieth Century
Authors: Honda Meiji , Yamane Shozo , Nakamura Hisashi
Published: August 2005

An interannual seesaw between the intensities of the Icelandic and Aleutian lows and its impact on surface climate observed during the twentieth century are investigated. In a recent period from the late 1960s to the early 1990s, their seesaw relationship was particularly apparent in late winter. The associated anomalies in surface air temperature were significant in many regions over the extratropical Northern Hemisphere except in central portions of the continents. The seesaw also modified the ocean–atmosphere exchange of heat and moisture extensively over the North Atlantic and North Pacific by changing evaporation and precipitation. Since the seesaw formation was triggered by eastward propagation of stationary Rossby wave trains from the North Pacific into the North Atlantic, anomalous circulation over the North Pacific in January was identified as a good precursor for February surface air temperatures in the Euro–Atlantic sector during that period.

The seesaw relationship between the two lows underwent multidecadal modulations during the twentieth century. It was weak in the mid-1950s through the mid-1960s, while it was particularly strong during the preceding period from the 1920s to the 1940s with its impact on surface temperatures as extensive as in the recent period. Although it reached maturity in January, the precursory signal of the seesaw in that early period was also found in the North Pacific one month earlier, which suggests that the formation was through essentially the same mechanisms as in the recent period.
The Heat Balance of the Western Hemisphere Warm Pool
Authors: Enfield David B. , Lee Sang-ki
Published: August 2005

The thermodynamic development of the Western Hemisphere warm pool and its four geographic subregions are analyzed. The subregional warm pools of the eastern North Pacific and equatorial Atlantic are best developed in the boreal spring, while in the Gulf of Mexico and Caribbean, the highest temperatures prevail during the early and late summer, respectively. For the defining isotherms chosen (≥27.5°, ≥28.0°, ≥28.5°C) the warm pool depths are similar to the mixed-layer depth (20–40 m) but are considerably less than the Indo–Pacific warm pool depth (50–60 m). The heat balance of the WHWP subregions is examined through two successive types of analysis: first by considering a changing volume (“bubble”) bounded by constant temperature wherein advective fluxes disappear and diffusive fluxes can be estimated as a residual, and second by considering a slab layer of constant dimensions with the bubble diffusion estimates as an additional input and the advective heat flux divergence as a residual output. From this sequential procedure it is possible to disqualify as being physically inconsistent four of seven surface heat flux climatologies: the NCEP–NCAR reanalysis (NCEP1) and the ECMWF 15-yr global reanalysis (ERA-15) because they yield a nonphysical diffusion of heat into the warm pools from their cooler surroundings, and the unconstrained da Silva and Southampton datasets because their estimated diffusion rates are inconsistent with the smaller rates of the better understood Indo–Pacific warm pool when the bubble analysis is applied to both regions. The remaining surface flux datasets of da Silva and Southampton (constrained) and Oberhuber have a much narrower range of slab surface warming (+25 ± 5 W m−2) associated with bubble residual estimates of total diffusion of –5 to –20 W m−2 (±5 W m−2) and total advective heat flux divergence of –2 to –14 W m−2 (±5 W m−2). The latter are independently confirmed by direct estimates using wind stress data and drifters for the Gulf of Mexico and eastern North Pacific subregions.
Urban Heat Island Assessment: Metadata Are Important
Authors: Peterson Thomas C. , Owen Timothy W.
Published: August 2005

Urban heat island (UHI) analyses for the conterminous United States were performed using three different forms of metadata: nightlights-derived metadata, map-based metadata, and gridded U.S. Census Bureau population metadata. The results indicated that metadata do matter. Whether a UHI signal was found depended on the metadata used. One of the reasons is that the UHI signal is very weak. For example, population was able to explain at most only a few percent of the variance in temperature between stations. The nightlights metadata tended to classify lower population stations as rural compared to map-based metadata while the map-based metadata urban stations had, on average, higher populations than urban nightlights. Analysis with gridded population metadata indicated that statistically significant urban heat islands could be found even when quite urban stations were classified as rural, indicating that the primary signal was coming from the relatively high population sites. If ∼30% of the highest population stations were removed from the analysis, no statistically significant urban heat island was detected. The implications of this work on U.S. climate change analyses is that, if the highest population stations are avoided (populations above 30 000 within 6 km), the analysis should not be expected to be contaminated by UHIs. However, comparison between U.S. Historical Climatology Network (HCN) time series from the full dataset and a subset excluding the high population sites indicated that the UHI contamination from the high population stations accounted for very little of the recent warming.
El Niño–La Niña Asymmetry in the Coupled Model Intercomparison Project Simulations*
Authors: An Soon-Il , Ham Yoo-Geun , Kug Jong-Seong , Jin Fei-Fei , Kang In-Sik
Published: August 2005

The El Niño–La Niña asymmetry was estimated in the 10 different models participating in the Coupled Model Intercomparison Project (CMIP). Large differences in the “asymmetricity” (a variance-weighted skewness) of SST anomalies are found between models and observations. Most of the coupled models underestimate the nonlinearity and only a few exhibit the positively skewed SST anomalies over the tropical eastern Pacific as seen in the observation. A significant association between the nonlinear dynamical heating (NDH) and asymmetricity in the model–ENSO indices is found, inferring that asymmetricity is caused mainly by NDH. Among the 10 models, one coupled GCM simulates the asymmetricity of the tropical SST realistically, and its simulation manifests a strong relationship between the intensity and the propagating feature of ENSO—the strong ENSO events moving eastward and the weak ENSO events moving westward—which is consistent with the observation. Interestingly, the coupled general circulation models, of which the ocean model is based on the one used by Bryan and Cox, commonly showed the reasonably positive skewed ENSO.

The decadal changes in the skewness, variance, and NDH of the model-simulated ENSO are also observed. These three quantities over the tropical eastern Pacific are significantly correlated to each other, indicating that the decadal change in ENSO variability is closely related to the nonlinear process of ENSO. It is also found that these decadal changes in ENSO variability are related to the decadal variation in the tropical Pacific SST, implying that the decadal change in the El Niño–La Niña asymmetry could manifest itself as a rectified change in the background state.
The Energetics of Ocean Heat Transport
Authors: Gnanadesikan Anand , Slater Richard D. , Swathi P. S. , Vallis Geoffrey K.
Published: August 2005

A number of recent papers have argued that the mechanical energy budget of the ocean places constraints on how the thermohaline circulation is driven. These papers have been used to argue that climate models, which do not specifically account for the energy of mixing, potentially miss a very important feedback on climate change. This paper reexamines the question of what energetic arguments can teach us about the climate system and concludes that the relationship between energetics and climate is not straightforward. By analyzing the buoyancy transport equation, it is demonstrated that the large-scale transport of heat within the ocean requires an energy source of around 0.2 TW to accomplish vertical transport and around 0.4 TW (resulting from cabbeling) to accomplish horizontal transport. Within two general circulation models, this energy is almost entirely supplied by surface winds. It is also shown that there is no necessary relationship between heat transport and mechanical energy supply.
Characteristics and Trends of River Discharge into Hudson, James, and Ungava Bays, 1964–2000
Authors: Déry Stephen J. , Stieglitz Marc , McKenna Edward C. , Wood Eric F.
Published: August 2005

The characteristics and trends of observed river discharge into the Hudson, James, and Ungava Bays (HJUBs) for the period 1964–2000 are investigated. Forty-two rivers with outlets into these bays contribute on average 714 km3 yr−1 [= 0.023 Sv (1 Sv ≡ 106 m3 s−1)] of freshwater to high-latitude oceans. For the system as a whole, discharge attains an annual peak of 4.2 km3 day−1 on average in mid-June, whereas the minimum of 0.68 km3 day−1 occurs on average during the last week of March. The Nelson River contributes as much as 34% of the daily discharge for the entire system during winter but diminishes in relative importance during spring and summer. Runoff rates per contributing area are highest (lowest) on the eastern (western) shores of the Hudson and James Bays. Linear trend analyses reveal decreasing discharge over the 37-yr period in 36 out of the 42 rivers. By 2000, the total annual freshwater discharge into HJUBs diminished by 96 km3 (−13%) from its value in 1964, equivalent to a reduction of 0.003 Sv. The annual peak discharge rate associated with snowmelt has advanced by 8 days between 1964 and 2000 and has diminished by 0.036 km3 day−1 in intensity. There is a direct correlation between the timing of peak spring discharge rates and the latitude of a river’s mouth; the spring freshet varies by 5 days for each degree of latitude. Continental snowmelt induces a seasonal pulse of freshwater from HJUBs that is tracked along its path into the Labrador Current. It is suggested that the annual upper-ocean salinity minimum observed on the inner Newfoundland Shelf can be explained by freshwater pulses composed of meltwater from three successive winter seasons in the river basins draining into HJUBs. A gradual salinization of the upper ocean during summer over the period 1966–94 on the inner Newfoundland Shelf is in accord with a decadal trend of a diminishing intensity in the continental meltwater pulses.
Multirater Agreement of Arthroscopic Grading of Knee Articular Cartilage
Authors: Marx Robert G. , Connor Jason , Lyman Stephen , Amendola Annunziato , Andrish Jack T. , Kaeding Christopher , McCarty Eric C. , Parker Richard D. , Wright Rick W. , Spindler Kurt P.
Published: August 2005

Background

Acute and chronic cartilage injury of the knee has an important impact on prognosis. The validity of the classification of such injuries is critical for prospective multicenter studies. The agreement among multiple surgeons at different institutions for articular cartilage lesions has not been established.

Hypothesis

Arthroscopic classification of articular cartilage lesions is reliable and reproducible and can be used for multicenter studies involving multiple surgeons.

Study Design

Cohort study (diagnosis); Level of evidence, 1.

Methods

A total of 6 surgeons from 5 centers reviewed 31 videos of articular cartilage lesions. With grade 2 and grade 3 combined for the analysis, observed agreement ranged from 81% to 94%, and kappa ranged from 0.34 to 0.87. An additional 22 videos comprising grade 2 and grade 3 lesions were analyzed, and the observed agreement was 80%, with an overall kappa of 0.47.

Conclusion

Arthroscopic grading of articular cartilage lesions is reproducible among surgeons at different centers.

Clinical Relevance

Articular cartilage lesions can be reliably classified among surgeons at different sites. Such reliability is important for multicenter clinical research studies involving arthroscopic knee surgery.
Tendon-Bone Interface Motion in Transosseous Suture and Suture Anchor Rotator Cuff Repair Techniques
Authors: Ahmad Christopher S. , Stewart Andrew M. , Izquierdo Rolando , Bigliani Louis U.
Published: August 2005

Background

Although many studies involving rotator cuff repair fixation have focused on ultimate fixation strength and ability to restore the tendon's native footprint, no studies have characterized the stability of the repair with regard to motion between the tendon and repair site footprint.

Hypothesis

Suture anchor fixation for rotator cuff repair has greater interface motion between tendon and bone than does transosseous suture fixation.

Study Design

Controlled laboratory study.

Methods

Twelve fresh-frozen human cadaveric shoulders were tested in a custom device to position the shoulder in internal and external rotations with simulated supraspinatus muscle loading. Tendon motion relative to the insertional footprint on the greater tuberosity was determined optically using a digital camera rigidly connected to the humerus, with the humerus positioned at 60° of internal rotation and 60° of external rotation. Testing was performed for the intact tendon, a complete supraspinatus tear, a suture anchor repair, and a transosseous tunnel repair.

Results

Difference in tendon-bone interface motion when compared with the intact tendon was 7.14 ± 3.72 mm for the torn rotator cuff condition, 2.35 ± 1.26 mm for the suture anchor repair, and 0.02 ± 1.18 mm for the transosseous suture repair. The transosseous suture repair demonstrated significantly less motion when compared with the torn rotator cuff and suture anchor repair conditions (P <. 05).

Conclusion

Transosseous suture repair compared with suture anchor repair demonstrated superior tendon fixation with reduced motion at the tendon-to-tuberosity interface.

Clinical Relevance

Development of new fixation techniques for arthroscopic and open rotator cuff repairs should attempt to minimize interface motion of the tendon relative to the tuberosity.
Trochlear Contact Pressures after Anteromedialization of the Tibial Tubercle
Authors: Beck Paul R. , Thomas Andre L. , Farr Jack , Lewis Paul B. , Cole Brian J.
Published: August 2005

Background

Anteromedialization is recommended for cartilage restoration of patellofemoral defects, with the presumption that it decreases contact pressures across the trochlea. No study has evaluated pressures on the trochlear side of the patellofemoral joint after anteromedialization of the tibial tubercle.

Hypothesis

Anteromedialization of the tibial tubercle decreases contact pressure across the trochlea.

Study Design

Controlled laboratory study.

Methods

Ten cadaveric knees were tested by placing an electroresistive pressure sensor on the femoral side of the patellofemoral joint. A validated model of nonweightbearing resisted extension was simulated by loading the extensor mechanism at 89.1 N and 178.2 N. Knees were tested 3 times per load at 30°, 60°, 90°, and 105°. The center of force and pressure across the patellofemoral articulation were compared before and after a reproducible and consistent anteromedialization.

Results

The mean center of force shifted medially after anteromedialization at 89.1 N and 178.2 N. At 89.1 N, the mean total contact pressure decreased significantly (P <. 05) at all angles, and at 178.2 N, it decreased significantly at 30°, 60°, and 90° of knee flexion. The mean lateral trochlear contact pressure decreased significantly (P <. 05) at all flexion angles at both 89.1 N and 178.2 N. The mean central trochlear contact pressure decreased significantly (P <. 05) at 30° with the 89.1-N and 178.2-N loads but increased significantly (P <. 05) at 90° with the 89.1-N load. The mean medial trochlear contact pressure increased significantly (P <. 05) at all flexion angles at 89.1 N and 178.2 N.

Conclusion

Anteromedialization shifts the contact force to the medial trochlea and decreases the mean total contact pressure.

Clinical Relevance

Anteromedialization decreases the mean total contact pressure while shifting contact pressure toward the medial trochlea. This study suggests that anteromedialization is appropriate for unloading the lateral trochlea. However, this procedure appears to have minimal benefit on central chondral defects, and it may actually increase the load in patients with medial defects.
A survey of transcutaneous blood gas monitoring among European neonatal intensive care units
Authors: Rüdiger Mario , Töpfer Kerstin , Hammer Hannes , Schmalisch Gerd , Wauer Roland R
Published: August 2005

Background

PCO2 and PO2 are important monitoring parameters in neonatal intensive care units (NICU). Compared to conventional blood gas measurements that cause significant blood loss in preterms, transcutaneous (tc) measurements allow continuous, non-invasive monitoring of blood gas levels. The aim of the study was to survey the usage and opinions among German speaking NICUs concerning tc blood gas monitoring.

Methods

A questionnaire was developed and sent to 56 head nurses of different NICUs in Germany, Switzerland and Austria.

Results

A completely answered questionnaire was obtained from 41 NICUs. In two of these units tc measurements are not performed. In most NICUs (77%), both PtcO2 and PtcCO2 are measured simultaneously. Most units change the sensors every 3 hours; however, the recommended temperature of 44°C is used in only 15% of units. In only 8% of units are arterial blood gases obtained to validate tc values. Large variations were found concerning the targeted level of oxygen saturation [median upper limit: 95% (range 80–100%); median lower limit: 86% (range 75–93%)] and PO2 [median upper limit: 70 mmHg (range 45–90 mmHg); median lower limit: 44 mmHg (range 30–60 mmHg)].

Conclusion

Our survey shows that the use of tc monitors remains widespread among German speaking NICUs, despite earlier data suggesting that their use had been abandoned in many NICUs worldwide. In addition, we suggest that the current method of monitoring oxygenation may not prevent hyperoxemia in preterm infants.
Inequalities in neighbourhood socioeconomic characteristics: potential evidence-base for neighbourhood health planning
Authors: Odoi Agricola , Wray Ron , Emo Marion , Birch Stephen , Hutchison Brian , Eyles John , Abernathy Tom
Published: August 2005

Background

Population health planning aims to improve the health of the entire population and to reduce health inequities among population groups. Socioeconomic factors are increasingly being recognized as major determinants of many aspects of health and causes of health inequities. Knowledge of socioeconomic characteristics of neighbourhoods is necessary to identify their unique health needs and enhance identification of socioeconomically disadvantaged populations. Careful integration of this knowledge into health planning activities is necessary to ensure that health planning and service provision are tailored to unique neighbourhood population health needs. In this study, we identify unique neighbourhood socioeconomic characteristics and classify the neighbourhoods based on these characteristics. Principal components analysis (PCA) of 18 socioeconomic variables was used to identify the principal components explaining most of the variation in socioeconomic characteristics across the neighbourhoods. Cluster analysis was used to classify neighbourhoods based on their socioeconomic characteristics.

Results

Results of the PCA and cluster analysis were similar but the latter were more objective and easier to interpret. Five neighbourhood types with distinguishing socioeconomic and demographic characteristics were identified. The methodology provides a more complete picture of the neighbourhood socioeconomic characteristics than when a single variable (e.g. income) is used to classify neighbourhoods.

Conclusion

Cluster analysis is useful for generating neighbourhood population socioeconomic and demographic characteristics that can be useful in guiding neighbourhood health planning and service provision. This study is the first of a series of studies designed to investigate health inequalities at the neighbourhood level with a view to providing evidence-base for health planners, service providers and policy makers to help address health inequity issues at the neighbourhood level. Subsequent studies will investigate inequalities in health outcomes both within and across the neighbourhood types identified in the current study.
Spam1-associated transmission ratio distortion in mice: Elucidating the mechanism
Authors: Martin-DeLeon Patricia A , Zhang Hong , Morales Carlos R , Zhao Yutong , Rulon Michelle , Barnoski Barry L , Chen Hong , Galileo Deni S
Published: August 2005

Background

While transmission ratio distortion, TRD, (a deviation from Mendelian ratio) is extensive in humans and well-documented in mice, the underlying mechanisms are unknown. Our earlier studies on carriers of spontaneous mutations of mouse Sperm Adhesion Molecule 1 (Spam1) suggested that TRD results from biochemically different sperm, due to a lack of transcript sharing through the intercellular cytoplasmic bridges of spermatids. These bridges usually allow transcript sharing among genetically different spermatids which develop into biochemically and functionally equivalent sperm.

Objectives

The goals of the study were to provide support for the lack of sharing (LOS) hypothesis, using transgene and null carriers of Spam1, and to determine the mechanism of Spam1-associated TRD.

Methods

Carriers of Spam1-Hyal5 BAC transgenes were mated with wild-type female mice and the progeny analyzed for TRD by PCR genotyping. Sperm from transgene and Spam1 null carriers were analyzed using flow cytometry and immunocytochemistry to detect quantities of Spam1 and/or Hyal5. Transgene-bearing sperm with Spam1 overexpression were detected by fluorescence in situ hybridization. In wild-type animals, EM studies of in situ transcript hybridization of testis sections and Northern analysis of biochemically fractionated testicular RNA were performed to localize Spam1 transcript. Finally, AU-rich motifs identified in the 3' UTR of Spam1 RNA were assayed by UV cross-linking to determine their ability to interact with testicular RNA binding proteins.

Results

The Tg8 line of transgene carriers had a significant (P < 0.001) TRD, due to reduced fertilizing ability of transgene-bearing sperm. These sperm retained large cytoplasmic droplets engorged with overexpressed Spam1 or Hyal5 protein. Caudal sperm from transgene carriers and caput sperm of null carriers showed a bimodal distribution of Spam1, indicating that the sperm in a male were biochemically different with respect to Spam1 quantities. Spam1 RNA was absent from the bridges, associated exclusively with the ER, and was shown to be anchored to the cytoskeleton. This compartmentalization of the transcript, mediated by cytoskeletal binding, occurs via protein interactions with 3' UTR AU-rich sequences that are likely involved in its stabilization.

Conclusion

We provide strong support for the LOS hypothesis, and have elucidated the mechanism of Spam1-associated TRD.
Efficient trapping of HIV-1 envelope protein by hetero-oligomerization with an N-helix chimera
Authors: Ou Wu , Silver Jonathan
Published: August 2005

Background

The N-heptad repeat region of the HIV-1 Transmembrane Envelope protein is a trimerization domain that forms part of a "six helix bundle" crucial to Envelope-mediated membrane fusion. N-heptad repeat peptides have been used as extracellular reagents to inhibit virus fusion.

Results

When expressed intracellularly with wild-type HIV-1 Envelope protein, the N-heptad repeat domain efficiently hetero-oligomerized with Envelope and trapped it in the endoplasmic reticulum or early Golgi, as indicated by lack of transport to the cell surface, absent proteolytic processing, and aberrant glycosylation.

Conclusion

Post-translational processing of HIV Envelope is very sensitive to an agent that binds to the N-heptad repeat during synthesis, suggesting that it might be possible to modify drugs that bind to this region to have transport-blocking properties.
Mutual repression betweenmshand Iro-C is an essential component of the boundary between body wall and wing inDrosophila
Authors: Villa-Cuesta Eugenia , Modolell Juan
Published: August 2005

During development, the imaginal wing disc of Drosophila is subdivided into territories separated by developmental boundaries. The best characterized boundaries delimit compartments defined by cell-lineage restrictions. Here, we analyze the formation of a boundary that does not rely on such restrictions, namely, that which separates the notum (body wall) and the wing hinge (appendage). It is known that the homeobox genes of the Iroquois complex (Iro-C) define the notum territory and that the distal limit of the Iro-C expression domain demarks the boundary between the notum and the wing hinge. However, it is unclear how this boundary is established and maintained. We now find that msh, a homeobox gene of the Msx family,is strongly expressed in the territory of the hinge contiguous to the Iro-C domain. Loss- and gain-of-function analyses show that msh maintains Iro-C repressed in the hinge, while Iro-C prevents high level expression of msh in the notum. Thus, a mutual repression between msh and Iro-C is essential to set the limit between the contiguous domains of expression of these genes and therefore to establish and/or maintain the boundary between body wall and wing. In addition, we find that msh is necessary for proper growth of the hinge territory and the differentiation of hinge structures. msh also participates in the patterning of the notum, where it is expressed at low levels.
RNF17, a component of the mammalian germ cell nuage, is essential for spermiogenesis
Authors: Pan Jieyan , Goodheart Mary , Chuma Shinichiro , Nakatsuji Norio , Page David C. , Wang P. Jeremy
Published: August 2005

Nuages are found in the germ cells of diverse organisms. However, nuages in postnatal male germ cells of mice are poorly studied. Previously, we cloned a germ cell-specific gene named Rnf17, which encodes a protein containing both a RING finger and tudor domains. Here, we report that RNF17 is a component of a novel nuage in male germ cells - the RNF17 granule, which is an electron-dense non-membrane bound spherical organelle with a diameter of 0.5 μm. RNF17 granules are prominent in late pachytene and diplotene spermatocytes, and in elongating spermatids. RNF17 granules are distinguishable from other known nuages, such as chromatoid bodies. RNF17 is able to form dimers or polymers both in vitro and in vivo, indicating that it may play a role in the assembly of RNF17 granules. Rnf17-deficient male mice were sterile and exhibited a complete arrest in round spermatids,demonstrating that Rnf17 encodes a novel key regulator of spermiogenesis. Rnf17-null round spermatids advanced to step 4 but failed to produce sperm. These results have shown that RNF17 is a component of a novel germ cell nuage and is required for differentiation of male germ cells.
Human Rights and Police Training in Transitional Societies: Exporting the Lessons of Northern Ireland
Authors: O'Rawe Mary
Published: August 2005

This article looks at police transformation in transitional societies through the prism of an analysis of police human rights training. Using Northern Ireland as its focus, this article posits key lessons to be considered in any society hoping to use the transitional moment to best effect—in terms of both institutional reform of the police and the wider peace building project. This article addresses how obstacles to inculcating a culture of human rights into any police organization mutate, or take on a heightened urgency, in transitional contexts. This article then draws conclusions with resonance, not just for Northern Ireland, but for policing change generally in transitional societies.
Virtuous Voyages in Penelope Aubin's Fiction
Authors: Gollapudi Aparna
Published: August 2005

Penelope Aubin's fiction incorporates elements from two popular genres of her day—travel fiction and the amatory novel—and adds to this melange a strident Christian morality. The result is that her narratives often realign the gender assumptions on which both travel and amatory fiction are based. Her female-centered travel narratives feature pious heroines endowed with endurance and fierce resourcefulness. Though her work also reveals the problematic position of Christian women within the grand imperial subtext of travel literature, Aubin does offer an alternative model of female adventure to early-eighteenth-century readers that blends piety with pleasure, thrill with theology.
Multiplex Human Papillomavirus Serology Based on In Situ–Purified Glutathione S-Transferase Fusion Proteins
Authors: Waterboer Tim , Sehr Peter , Michael Kristina M , Franceschi Silvia , Nieland John D , Joos Thomas O , Templin Markus F , Pawlita Michael
Published: August 2005

Background: More than 100 different human papillomaviruses (HPVs) can cause proliferative diseases, many of which are malignant, such as cervical cancer. HPV serology is complex because infection and disease lead to distinct type-specific antibody responses. Using bead-based technology, we have developed an assay platform that allows the simultaneous detection of antibodies against up to 100 in situ affinity–purified recombinant HPV proteins.

Methods: Twenty-seven HPV proteins were expressed as glutathione S-transferase fusion proteins and affinity-purified in one step by incubation of glutathione-displaying beads in bacterial lysate. Spectrally distinct bead sets, each carrying one particular antigen, were mixed, incubated with serum, and differentiated in a flow cytometer-like analyzer (xMAP; Luminex Corp). Antibodies bound to the antigens were detected via fluorescent secondary reagents. We studied 756 sera from 2 case-control studies of cervical cancer.

Results: Glutathione S-transferase fusion proteins bound with high affinity to glutathione-displaying beads (Kd = 6.9 × 10−9 mol/L). The dynamic range of multiplex serology covered 1.5 orders of magnitude, and antibodies were detected at serum dilutions >1:1 000 000. Imprecision (median CV) was ≤5.4%, and assay reproducibility was high (R2 = 0.97). Results on clinical samples showed high concordance with ELISA (κ = 0.846), but multiplex serology exhibited increased detection of weak antibody responses. Antibodies to the E6 oncoproteins of the rare HPV types 52 and 58 were associated with cervical cancer (P <0.001).

Conclusion: Multiplex serology enables antibody analyses of large numbers of sera against up to 100 antigens in parallel and has the potential to replace ELISA technology.