bluuebunny/crossref_metadata_2025 huggingface dataset:
Five‐year follow up of a randomised controlled trial comparing NovaSure and ThermaChoice endometrial ablation
Authors: Kleijn JH , Engels R , Bourdrez P , Mol BWJ , Bongers MY
Published: July 2007

Objective  We have previously reported that NovaSure® was more effective than balloon ablation at 12 months follow up in the treatment of menorrhagia. In this paper, we report the 5‐year outcome of this study. The objective was to evaluate amenorrhoea rates, hysterectomy rate, and quality of life associated with the bipolar impedance‐controlled endometrial ablation technique (NovaSure) in comparison with balloon ablation technique (ThermaChoice®) at 5 years after administration.

Design  Double‐blind randomised controlled trial, 2:1 randomisation NovaSure versus ThermaChoice.

Setting  A teaching hospital with 500 beds in the Netherlands.

Population  A total of 126 premenopausal women suffering from menorrhagia with a pictorial blood loss assessment count ≥150 without intracavitary abnormalities.

Methods  Women were randomly allocated to bipolar radio‐frequency ablation and balloon ablation in a 2:1 ratio.

Main outcome measures  The main outcome measures were amenorrhoea rate, hysterectomies, and health‐related quality of life (HRQol) as reported at 5 year follow up.

Results  At 5 years of follow up, the total response rate was 96% in the bipolar group and 90% in the balloon group. Amenorrhoea was reported in the bipolar group by 48% of women and in the balloon arm by 32% (relative risk 1.6 [.93–2.6]). There were eight women in the bipolar group (9.8%) and five in the balloon group (12.9%) who had undergone a hysterectomy. Furthermore, there was a significant equal improvement of HRQoL over time in both groups.

Conclusions  At 5 years follow up, bipolar thermal ablation was superior over balloon ablation in the treatment of menorrhagia.
Spousal Concordance in Health Behavior Change
Authors: Falba Tracy A. , Sindelar Jody L.
Published: July 2007

Objective. This study examines the degree to which a married individual's health habits and use of preventive medical care are influenced by his or her spouse's behaviors.

Study Design. Using longitudinal data on individuals and their spouses, we examine changes over time in the health habits of each person as a function of changes in his or her spouse's health habits. Specifically, we analyze changes in smoking, drinking, exercising, cholesterol screening, and obtaining a flu shot.

Data Source. This study uses data from the Health and Retirement Study (HRS), a nationally representative sample of individuals born between 1931 and 1941 and their spouses. Beginning in 1992, 12,652 persons (age‐eligible individuals as well as their spouses) from 7,702 households were surveyed about many aspects of their life, including health behaviors, use of preventive services, and disease diagnosis.

Sample. The analytic sample includes 6,072 individuals who are married at the time of the initial HRS survey and who remain married and in the sample at the time of the 1996 and 2000 waves.

Principal Findings. We consistently find that when one spouse improves his or her behavior, the other spouse is likely to do so as well. This is found across all the behaviors analyzed, and persists despite controlling for many other factors.

Conclusions. Simultaneous changes occur in a number of health behaviors. This conclusion has prescriptive implications for developing interventions, treatments, and policies to improve health habits and for evaluating the impact of such measures.
Judges in Politics: England
Authors: Griffith J. A. G.
Published: July 2007

HER MAJESTY'S JUDGES ARE BY NATURE CONSERVATIVE BECAUSE their function is to apply existing law, to uphold a system not to subvert it. But they are not by nature reactionary, do not have any necessary opposition to new ideas, must indeed seek to fit political novelties expressed in statutory terms into the existing order. But, by their background and more importantly by their training, they are cautious, have seen it before, and in interpreting Acts of Parliament still work on the basis of certain assumptions which are also widely shared by those in the street below their windows, along the embankment at Westminster, and by the man in the passing Clapham omnibus. These assumptions are that Parliament does not intend to enact anydung so radical as to upset the constitution, or to deprive private persons of life, liberty or property by inadvertence but only by express words, and that Parliament generally enacts within what the judges regard as the fundamental political and economic structure of contemporary Anglo-Saxon society.
The Desired ‘One’: Thinking the Woman in the Nation
Authors: Das Anirban , Sen Chaudhuri Ritu
Published: July 2007

A review of the secondary literature on the way nationalist thought in colonial India conceived ‘woman’ shows three broad strands. One is the perspective of the history of art, which studies the genealogy of the iconic symbolisation of women. The remaining stands have similar objects of knowledge (the nationalist representation of women in terms of the debi) but differ in their foci of attention. The first is concerned with the (role of the) woman in nationalist thought and how ‘real’ women had responded to that construction. The other focuses on the processes of nation building in the colony to reach its gendered aspects. We finally make a case for a synthesis of these through a few instances.
Transmissi ons and Transformations: Global Peace Movements between the Hague Conferences and World War I
Authors: Chao Anne
Published: July 2007

The meetings of the Hague Peace Conference and the Lake Mohonk Conference on International Arbitration at the turn of twentieth century stimulated renewed interest in organizations such as the American Peace Society, and inspired the formation of the Cosmopolitan Club on university campuses. Around 1910, the European Corda Fratres joined forces with the Association of Cosmopolitan Clubs. Hu Shi, president of the Cornell Cosmopolitan Club in 1913, became a convert to the cause of peace, and defended his pacifism in war‐stricken China throughout his life. In the same period, the Japan Peace Society worked closely with many American peace organizations. From Europe to America to Asia, most peace proponents advocated arbitration, conciliation, international laws, the establishment of an international court and an international congress. Their shared language of the discourse on pacifism demonstrates vividly an instance of the transmigration of ideas across spatial and cultural boundaries.
RESPONSE OF LAMINARIA SACCHARINA (PHAEOPHYTA) GROWTH AND PHOTOSYNTHESIS TO SIMULTANEOUS ULTRAVIOLET RADIATION AND NITROGEN LIMITATION1
Authors: Davison Ian R. , Jordan Terry L. , Fegley Jill C. , Grobe Carl W.
Published: July 2007

The brown macroalga Laminaria saccharina (L.) J. V. Lamour. was grown in large outdoor tanks at 50% ambient solar radiation for 3–4 weeks in July and August of 2000, 2001, and 2002, in either ambient or nitrogen (N)–enriched seawater and in either ambient light [PAR + ultraviolet radiation (UVR)] or ambient light minus UVR. Growth, N‐content, photosynthetic pigments, and RUBISCO content increased in N‐enriched seawater, indicating N‐limitation. UVR inhibited growth, but this inhibition was ameliorated by N‐enrichment. The response of growth to UVR could not be explained by changes in respiration and photosynthesis. Gross light‐saturated photosynthesis (Pmax) remained unaffected by UVR but was significantly higher under N‐enrichment, as was dark respiration (Rd). UVR had no effect on pigments or N content. However, RUBISCO contents were low in the presence of UVR, reflecting the overall change in soluble cellular protein. Overall, our data indicate that the response to UVR in L. saccharina depends on other environmental factors, such as N, and these effects need to be considered when evaluating the response of macroalgae to increased UVR.
THERMAL ECOPHYSIOLOGY OF LAURENCIA PACIFICA AND LAURENCIA NIDIFICA (CERAMIALES, RHODOPHYTA) FROM TROPICAL AND WARM‐TEMPERATE REGIONS1
Authors: Padilla‐Gamiño Jacqueline L. , Carpenter Robert C.
Published: July 2007

Laurencia is a globally distributed genus with about 80 species (order Ceramiales) that inhabit tropical, subtropical, and warm‐temperate regions of both sides of the Atlantic and Indo‐Pacific oceans. This study investigated how two species of Laurencia distributed in different thermal environments (California and Hawaii) varied in their photosynthetic responses to temperature. The thermal ecophysiology of both species was investigated at different temporal scales (short‐term responses and seasonal acclimatization) using oxygen evolution and pulse‐amplitude‐modulated (PAM) fluorometry. Our results indicated that seasonal acclimatization of both species of Laurencia influenced the short‐term photosynthetic response at both locations. Greater seasonal differences in the photosynthetic performance were observed for L. pacifica Kylin, which reflects the ability of this species to acclimatize to local environmental conditions characterized by short‐term fluctuations and a broader annual temperature range. Photosynthetic performance of L. nidifica J. Agardh was consistent with the less variable local environment (no short‐term fluctuations and a narrower temperature range). These results suggest that acclimatization to temperature variability in the environment can influence the degree of flexibility of physiological responses of species in this genus.
International Nongovernmental Organizations and Deforestation: Good, Bad, or Irrelevant?*
Authors: Shandra John M.
Published: July 2007

Objective. This research adds to our understanding of environmental degradation by evaluating the “contested” role international nongovernmental organizations play in managing environmental problems.

Methods. I use cross‐national data for a sample of up to 70 nations to examine the effect of international nongovernmental organizations on deforestation for the period of 1990 to 2000. The models also include relevant controls for gross national product, economic growth, population growth, democracy, government expenditures, domestic investment, forest stocks, exports, multinational corporations, and structural adjustment.

Results. The main findings indicate that nations with higher levels of international nongovernmental organizations presence have lower levels of deforestation. I also examine the effects of international nongovernmental organizations at different levels of democracy by including an interaction term between international nongovernmental organizations and democracy. In doing so, I find that international nongovernmental organizations continue to reduce deforestation. However, they reduce deforestation more at higher rather than at lower levels of democracy.

Conclusions. This research illustrates that international nongovernmental organizations reduce deforestation despite claims to the contrary. However, their effectiveness appears to be affected by the level of democracy in a nation.
Smaller Isn't Always Better: School Size and School Participation Among Young People*
Authors: Lay J. Celeste
Published: July 2007

Objective. Although political scientists studying the role of schools on political socialization have focused most of their efforts on curriculum, mainly civic education, education scholars have long recognized that schools influence outcomes through much more than curriculum and have examined school organization extensively, including school size. Much of the recent literature on school size supports smaller schools. The objective of this article is to examine the effect of school size on two political socialization outcomes: adolescent participation in school activities and volunteering. These outcomes are important because they are related to later adult participation.

Method. A nationwide survey is used to conduct regression analyses as the primary method.

Results. The results show limited support for smaller schools, even for those groups who are believed to benefit most significantly from small schools: racial minorities, low‐income students, and underachievers.

Conclusion. I conclude with an appeal for caution among education reformers seeking to downsize schools and a recommendation to political socialization scholars to expand their analyses beyond civic education curriculum.
Circadian Variation in QT Dispersion Determined from a 12‐Lead Holter Recording: A Methodological Study of an Age‐ and Sex‐Stratified Group of Healthy Subjects
Authors: Hansen Stig , Rasmussen Verner , Larsen Klaus , Torp‐Pedersen Christian , Jensen Gorm Boje
Published: July 2007

Background: QT dispersion is considered to reflect inhomogeneity of myocardial repolarization.

Method: The circadian variation of QT interval dispersion was examined in 95 healthy subjects using 24‐hour Holter monitoring. Three different methods of lead selection were applied: all 12 leads (QTdisp 12), only precordial leads (QTdisp 6), and the pair of leads selected at 3 a.m. in which the longest and shortest QT intervals were found in each individual subject (QTdisp 2).

Results: A preliminary methodological study including measurements from every minute in 10 subjects revealed no significant circadian variation using mean values of QTdisp 12, QTdisp 6, or QTdisp 2 obtained every hour, every 2, or every 4 hours, except in QTdisp 6, which demonstrated a significant circadian variation (P < 0.01) in 1‐hour measurements. Analysis of all 95 subjects using measurements obtained every 4 hours revealed a significant circadian variation in QTdisp 12 and QTdisp 6 (P < 0.0001), whereas no circadian variation was seen in QTdisp 2. A subdivision into 10‐year age groups revealed that subjects at age >50 years had a significant circadian variation in QTdisp 12 and QTdisp 6, but not in QTdisp 2. Only in males a significant circadian variation was seen in QTdisp 12 (P < 0.0001), whereas QTdisp 6 demonstrated a circadian variation both in females (P < 0.001) and in males (P < 0.0001).

Conclusions: Selection of leads is of crucial importance for repetitive measurements of QT dispersion. Circadian variation was detected in subjects over 50 years of age, when all 12 or only the 6 precordial leads were taken into account.
Pacemaker Longevity: The World's Longest‐Lasting VVI Pacemaker
Authors: Katz David , Akiyama Toshio
Published: July 2007

Objective: To describe VVI‐pacemaker longevity by model type at our institution and report on a long‐lasting model and the longest‐lasting pacemaker to be described in the literature.

Background: Cardiac pacemakers are becoming increasingly common in the United States. Presently their batteries are expected to last up to 12 years. Pacemaker generator change is associated with increased cost to the health care system and is inconvenient for patients.

Methods: After identifying a group of very long‐lasting CPI Microlith 605 VVI pulse generators, we reviewed records on all patients who had either Guidant or Medtronic pulse generator explantation at our institution over a 10‐year period. Average longevities were calculated for all VVI pacemakers, four common VVI models, and the CPI Microlith 605.

Results: A total of 105 VVI‐programmed pacemakers were identified. Their average longevity was 7.2 years. The two most common Medtronic VVI‐programmed pacemakers explanted were the Thera (7.1 years) and Kappa (7.3 years). The two most common Guidant/CPI models were the Vigor (4.2 years) and Discovery (5.7 years). The CPI Microlith 605 (19.2 years) lasted more than 26 years in one patient before being explanted.

Conclusion: At a time when pacemakers are being used more frequently, pacemaker longevity may decrease as a result of the use of dual‐chamber pacing systems. In our study, the CPI Microlith 605 had an average longevity more than twice that of all other VVI pacemakers. We also report on a pulse generator that lasted 26.3 years.
Mental Stress May Induce QT‐Interval Prolongation and T‐Wave Notching
Authors: Andrássy Gábor , Szabo Attila , Ferencz Gyöngyvér , Trummer Zsófia , Simon Eszter , Tahy Ádám
Published: July 2007

Background: The effects of active and passive mental stress (PMS) on the QT interval were studied by using an intraindividual regression method of QT‐interval correction for heart rate.

Methods: Thirty healthy males (age 21.2 ± 1.8 years) performed a mental arithmetic for 1 minute, which was considered as active mental stress (AMS) because of the performance requirement. A 1‐minute unpleasant video clip was used for PMS. Two baseline and two (an early and a late) ECGs were prepared in both mental stress periods. The individual QT–RR relationship was assessed by linear regression analysis of 7–15 (11.0 ± 1.9) controlled QT–RR data pairs, also obtained from ECGs gained during a successive set of 9 isometric stretching exercises.

Results: Heart rate has increased significantly at both measurements in response to AMS (P < 0.0001), but not in response to passive stress. QTc significantly prolonged early in AMS (P = 0.0004), then normalized by the end of the period. During PMS, no significant QTc changes were observed. The evolution of bifid T waves was noted in 14 subjects: 8 presented bifid T waves during both AMS and exercise, and 6 during only exercise.

Conclusions: AMS and PMS elicit different cardiovascular reactions. Our results indicate that changes in the autonomic tone, probably abrupt sympathetic predominance, may cause QTc prolongation and bifid T waves. This suggests that besides stress quality and intensity, the dynamics of stress application and perception also influence repolarization.
Childhood Family, Ethnicity, and Drug Use Over the Life Course
Authors: Cubbins Lisa A. , Klepinger Daniel H.
Published: July 2007

Using multiply imputed data from 5 waves of the National Longitudinal Survey of Youth (N = 8,294), we investigated whether childhood family characteristics and childhood religious affiliation explain ethnic differences in marijuana and cocaine use in the last year. None of the childhood factors explained ethnic differences in drug use, though ethnicity and several childhood factors had age‐specific effects. Over the life course from young adulthood to middle age, ethnic differences in drug use changed and the effect of childhood religious affiliation declined. Having a more intellectually rich family in childhood increased the risk of drug use at younger ages but reduced it at older ages. The study demonstrates the significance of childhood family experiences for understanding adult drug use.
Living in the Gray: Women’s Experiences of Missing the Marital Transition
Authors: Sharp Elizabeth A. , Ganong Lawrence
Published: July 2007

Given the increasing trend of women delaying (or forgoing) marriage and the minimal scholarship on women’s reflections of their life course trajectories, the purpose of the study was to examine the lived experience of White, college‐educated women aged 28 – 34 years who have not married. Using descriptive phenomenology methodology, 32 interviews were conducted with 10 never‐married women. Results suggested that their experiences were marked by uncertainty. The women were intensely reflecting on their life pathways, evaluating themselves, and enacting strategies to manage the pervasive uncertainty they felt. Implications about life course expectations and decisions, coping strategies, and experiences of “missed” transitions and related consequences are discussed.
Racial and Ethnic Differences in the Timing of First Marriage and Smoking Cessation
Authors: Weden Margaret , Kimbro Rachel Tolbert
Published: July 2007

Using data from the National Longitudinal Survey of Youth 1979 (N = 4,050), we consider the relationship between the timing of family formation and positive changes in health behavior. Theories that predict both positive and negative associations are tested. The findings suggest that both mechanisms operate and that the direction of the association depends on the respondent’s race or ethnicity. Whites who marry early are less likely to quit smoking, whereas Whites who marry on time and Blacks and Hispanics who marry at all ages are more likely to quit. The analysis refines the understanding of how family formation shapes changes in health behaviors differentially across the life course, and it underscores the difference in this process for individuals from different racial and ethnic backgrounds.
Branched chain mechanism of polymerization and ultrastructure of prion protein amyloid fibrils
Authors: Baskakov Ilia V.
Published: July 2007

The discovery of prion disease and the establishment of the protein only hypothesis of prion propagation raised substantial interest in the class of maladies referred to as conformational diseases. Although significant progress has been made in elucidating the mechanisms of polymerization for several amyloidogenic proteins and peptides linked to conformational disorders and solving their fibrillar 3D structures, studies of prion protein amyloid fibrils and their polymerization mechanism have proven to be very difficult. The present minireview introduces the mechanism of branched‐chain reaction for describing the peculiar kinetics of prion polymerization and summarizes our current knowledge about the substructure of prion protein amyloid fibrils.
A review of catchment management in the new context of drinking water safety plans
Authors: Keirle Robert , Hayes Colin
Published: July 2007

By managing a catchment effectively, the range and amount of contaminants entering waters used for public water supply can be reduced, with resultant benefits for both water companies and consumers. Consequently, catchment management is increasingly being recognised as being at the heart of the water environment. An overview of current and previous catchment management initiatives is given, along with the European Landscape Convention, which could be used as a vehicle for the implementation of a national catchment management strategy. The adoption of the drinking water safety plan approach is strongly advocated by the World Health Organisation, and effective catchment management underpins this approach. Effective management of our catchments will also make a significant contribution to meeting our obligations under the Water Framework Directive, by helping to address the serious issue of diffuse pollution from agriculture.
Estimating Attenuation of Ultraviolet Radiation in Streams: Field and Laboratory Methods
Authors: Belmont Patrick , Hargreaves Bruce R. , Morris Donald P. , Williamson Craig E.
Published: July 2007

We adapted and tested a laboratory quantitative filter pad method and field‐based microcosm method for estimating diffuse attenuation coefficients (Kd) of ultraviolet radiation (UVR) for a wide range of stream optical environments (Kd320 = 3–44 m−1). Logistical difficulties of direct measurements of UVR attenuation have inhibited widespread monitoring of this important parameter in streams. Suspended sediment concentrations were manipulated in a microcosm, which was used to obtain direct measurements of diffuse attenuation. Dissolved and particulate absorption measurements of samples from the microcosm experiments were used to calibrate the laboratory method. Conditions sampled cover a range of suspended sediment (0–50 mg L−1) and dissolved organic carbon concentrations (1–4 mg L−1). We evaluated four models for precision and reproducibility in calculating particulate absorption and the optimal model was used in an empirical approach to estimate diffuse attenuation coefficients from total absorption coefficients. We field‐tested the laboratory method by comparing laboratory‐estimated and field‐measured diffuse attenuation coefficients for seven sites on the main stem and 10 tributaries of the Lehigh River, eastern Pennsylvania, USA. The laboratory‐based method described here affords widespread application, which will further our understanding of how stream optical environments vary spatially and temporally and consequently influence ecological processes in streams.
Fluoroquinolone Antibiotics Having the Potential to Interfere with Fluorescence‐Based Diagnosis†
Authors: Matchette L. Stephanie , Agrawal Anant , Pfefer T. Joshua
Published: July 2007

Fluorescence, both intrinsic and exogenously induced, is being used for diagnosis of abnormal tissue. Excitation wavelengths used by these methods range from 320 to 450 nm. The presence of absorbing or fluorescing drugs is rarely taken into account by practitioners of fluorescence diagnosis and has the potential to yield false‐positive or false‐negative results. Our aim is to quantify this potential by (1) comparing the quantum yield of fluoroquinolone antibiotics to those of known tissue fluorophores and (2) taking into account drug concentrations in the tissue during treatment. Quantum yields are determined relative to a working standard of Rhodamine 6G in ethanol. The working standard was calibrated against a fluorescein standard. We concentrated our initial efforts on (1) the fluoroquinolone antibiotics, ciprofloxacin, norfloxacin and ofloxacin and (2) the intrinsic tissue fluorophores, NADH, FAD and protoporphyrin IX. When ciprofloxacin, norfloxacin and ofloxacin were excited at wavelengths 310–390 nm, emission occurred from 350 to 650 nm with quantum yields ranging from 0.03 to 0.3. Quantum yields for intrinsic fluorophores excited at their peak absorption wavelengths were 0.02 (NADH, 340 nm), 0.035 (FAD, 450 nm) and 0.087 (protoporphyrin IX, 408 nm). A review of the literature shows that these fluoroquinolones have a large volume of distribution and can be found in high concentrations in almost every organ during a treatment regimen. The product of the drug tissue concentration and quantum yield, which we term the fluorescence effective concentration, is such that it is likely these fluoroquinolones will interfere during fluorescence diagnosis techniques.
Helicobacter pylori infection in hepatic encephalopathy: Relationship to plasma endotoxins and blood ammonia
Authors: Abdel‐Hady Hassan , Zaki Ali , Badra Gamal , Lotfy Mahmoud , Selmi Carlo , Giorgini Alessia , El‐Sayed Mohamed , Badr Reda
Published: July 2007

Background/Aim:  Hepatic encephalopathy (HE) is frequently observed in patients with advanced liver disease and manifests a wide variety of neuropsychiatric signs and symptoms. Ammonia toxicity and bacterial endotoxins have been suggested as key determinants of HE onset whereas a role for Helicobacter pylori infection has not been established. We investigated the correlation between H. pylori infection and HE severity (evaluated through functional tests) in 60 outpatients with established liver cirrhosis and 20 non‐cirrhotic controls.

Methods:  Fasting arterial blood ammonia, plasma endotoxins, and H. pylori infection status were investigated in all subjects.

Results:  H. pylori infection was documented in 35/60 (58%) patients and in 6/20 (30%) controls (P = 0.039). Significant differences were observed between patients with and withoutHE for age, presence of ascites, fasting arterial blood ammonia, plasma endotoxin, and H. pylori infection. Further, a significant increase in fasting arterial blood ammonia and plasma endotoxin was associated with H. pylori infection in cirrhotic patients. Last, medical treatment of H. pylori infection led to a significant decrease in HE severity and fasting arterial blood ammonia levels.

Conclusion:  In conclusion, we submit that H. pylori infection might, in fact, play a role in increasing the circulating levels of ammonia and endotoxins in cirrhotic patients, thus facilitating the onset of HE.
Performance comparison of two commercial BGO‐based PET/CT scanners using NEMA NU 2‐2001
Authors: Bolard Grégory , Prior John O. , Modolo Luca , Bischof Delaloye Angelika , Kosinski Marek , Wastiel Claude , Malterre Jérôme , Bulling Shelley , Bochud François , Verdun Francis R.
Published: July 2007

Combined positron emission tomography and computed tomography (PET/CT) scanners play a major role in medicine for in vivo imaging in an increasing number of diseases in oncology, cardiology, neurology, and psychiatry. With the advent of short‐lived radioisotopes other than and newer scanners, there is a need to optimize radioisotope activity and acquisition protocols, as well as to compare scanner performances on an objective basis. The Discovery‐LS (D‐LS) was among the first clinical PET/CT scanners to be developed and has been extensively characterized with older National Electrical Manufacturer Association (NEMA) NU 2‐1994 standards. At the time of publication of the latest version of the standards (NU 2‐2001) that have been adapted for whole‐body imaging under clinical conditions, more recent models from the same manufacturer, i.e., Discovery‐ST (D‐ST) and Discovery‐STE (D‐STE), were commercially available. We report on the full characterization both in the two‐ and three‐dimensional acquisition mode of the D‐LS according to latest NEMA NU 2‐2001 standards (spatial resolution, sensitivity, count rate performance, accuracy of count losses, and random coincidence correction and image quality), as well as a detailed comparison with the newer D‐ST widely used and whose characteristics are already published.
Sentential, lexical, and acoustic effects on the perception of word boundaries
Authors: Mattys Sven L. , Melhorn James F.
Published: July 2007

This study investigates the effects of sentential context, lexical knowledge, and acoustic cues on the segmentation of connected speech. Listeners heard near-homophonous phrases (e.g., ∕plʌmpaɪ∕ for “plum pie” versus “plump eye”) in isolation, in a sentential context, or in a lexically biasing context. The sentential context and the acoustic cues were piloted to provide strong versus mild support for one segmentation alternative (plum pie) or the other (plump eye). The lexically biasing context favored one segmentation or the other (e.g., ∕skʌmpaɪ∕ for “scum pie” versus *“scump eye,” and ∕lʌmpaɪ∕, for “lump eye” versus *“lum pie,” with the asterisk denoting a lexically unacceptable parse). A forced-choice task, in which listeners indicated which of two words they thought they heard (e.g., “pie” or “eye”), revealed compensatory mechanisms between the sources of information. The effect of both sentential and lexical contexts on segmentation responses was larger when the acoustic cues were mild than when they were strong. Moreover, lexical effects were accompanied with a reduction in sensitivity to the acoustic cues. Sentential context only affected the listeners’ response criterion. The results highlight the graded, interactive, and flexible nature of multicue segmentation, as well as functional differences between sentential and lexical contributions to this process.
Gap duration discrimination for frequency-asymmetric gap markers: Psychophysical and electrophysiological findings
Authors: Grose John H. , Hall Joseph W. , Buss Emily
Published: July 2007

This study investigated gap duration discrimination (GDD) for frequency-asymmetric gap markers, where one marker was a two-tone complex consisting of a primary tone and a secondary tone, and the other marker was the primary tone alone. Three experiments were undertaken to examine the order effect wherein performance is better when the two-tone marker is the leading marker than when it is the trailing marker. Experiment 1 demonstrated that GDD for frequency-asymmetric markers is intermediate between the boundaries of within-frequency-channel versus across-frequency-channel processing. Experiment 2 compared psychophysical performance with auditory brainstem responses (ABRs) elicited by the same stimuli. Whereas GDD thresholds were elevated for a complex trailing marker relative to a within-frequency-channel baseline, ABRs elicited by the complex marker were more robust. Experiment 3 tested the hypothesis that poor GDD performance with frequency-asymmetric markers is due to some form of nonenergetic, or informational, masking. The results did not support a role for informational masking conferred by synthetic listening; however, informational masking conferred by the occurrence of novel spectral events provided a parsimonious account. One possible interpretation is that the capacity to accurately encode a gap is undermined by the occurrence of novel spectral events that engage limited attentional resources.
Effects of acoustic parameters on bubble cloud dynamics in ultrasound tissue erosion (histotripsy)
Authors: Xu Zhen , Hall Timothy L. , Fowlkes J. Brian , Cain Charles A.
Published: July 2007

High intensity pulsed ultrasound can produce significant mechanical tissue fractionation with sharp boundaries (“histotripsy”). At a tissue-fluid interface, histotripsy produces clearly demarcated tissue erosion and the erosion efficiency depends on pulse parameters. Acoustic cavitation is believed to be the primary mechanism for the histotripsy process. To investigate the physical basis of the dependence of tissue erosion on pulse parameters, an optical method was used to monitor the effects of pulse parameters on the cavitating bubble cloud generated by histotripsy pulses at a tissue-water interface. The pulse parameters studied include pulse duration, peak rarefactional pressure, and pulse repetition frequency (PRF). Results show that the duration of growth and collapse (collapse cycle) of the bubble cloud increased with increasing pulse duration, peak rarefactional pressure, and PRF when the next pulse arrived after the collapse of the previous bubble cloud. When the PRF was too high such that the next pulse arrived before the collapse of the previous bubble cloud, only a portion of histotripsy pulses could effectively create and collapse the bubble cloud. The collapse cycle of the bubble cloud also increased with increasing gas concentration. These results may explain previous in vitro results on effects of pulse parameters on tissue erosion.
Age-related differences in the acoustic characteristics of male leopard seals, Hydrurga leptonyx
Authors: Rogers Tracey L.
Published: July 2007

During the breeding season, the underwater vocalizations and calling rates of adult male leopard seals are highly stereotyped. In contrast, sub-adult males have more variable acoustic behavior. Although adult males produce only five stereotyped broadcast calls as part of their long-range underwater breeding displays the sub-adults have a greater repertoire including the adult-like broadcast calls, as well as variants of these. Whether this extended repertoire has a social function is unknown due to the paucity of behavioral data for this species. The broadcast calls of the sub-adults are less stereotyped in their acoustic characteristics and they have a more variable calling rate. These age-related differences have major implications for geographic variation studies, where the acoustic behavior of different populations are compared, as well as for acoustic surveying studies, where numbers of calls are used to indicate numbers of individuals present. Sampling regimes which unknowingly include recordings from sub-adult animals will artificially exaggerate differences between populations and numbers of calling animals. The acoustic behavior of sub-adult and adult male leopard seals were significantly different and although this study does not show evidence that these differences reflect vocal learning in the male leopard seal it does suggest that contextual learning may be present.
Frequency modulation detection: Effects of age, psychophysical method, and modulation waveform
Authors: He Ning-ji , Mills John H. , Dubno Judy R.
Published: July 2007

As part of an ongoing study of auditory aging, detection of sinusoidal and quasitrapezoidal frequency modulation (FM) was measured with a 5-Hz modulation frequency and 500- and 4000-Hz carriers in two experiments. In Experiment 1, psychometric functions for FM detection were measured with several modulation waveform time patterns in younger adults with normal hearing. Detection of a three-cycle modulated signal improved when its duration was extended by a preceding unmodulated cycle, an effect similar to adding a modulated cycle. In Experiment 2, FM detection was measured for younger and older adults with normal hearing using two psychophysical methods. Similar to frequency discrimination, FM detection was poorer in older than younger subjects and age-related differences were larger at 500Hz than at 4000Hz, suggesting that FM detection with low modulation frequencies and frequency discrimination may share common underlying mechanisms. One mechanism is likely related to temporal information coded by neural phase locking which is strong at low frequencies and decreases with increasing frequency, as observed in animals. The frequency-dependent aging effect suggests that this temporal mechanism may be affected by age. The effect of psychophysical method was sizable and frequency dependent, whereas the effect of modulation waveform was minimal.
Via Freedom to Coercion: The Emergence of Costly Punishment
Authors: Hauert Christoph , Traulsen Arne , Brandt Hannelore , Nowak Martin A. , Sigmund Karl
Published: July 2007

In human societies, cooperative behavior in joint enterprises is often enforced through institutions that impose sanctions on defectors. Many experiments on so-called public goods games have shown that in the absence of such institutions, individuals are willing to punish defectors, even at a cost to themselves. Theoretical models confirm that social norms prescribing the punishment of uncooperative behavior are stable—once established, they prevent dissident minorities from spreading. But how can such costly punishing behavior gain a foothold in the population? A surprisingly simple model shows that if individuals have the option to stand aside and abstain from the joint endeavor, this paves the way for the emergence and establishment of cooperative behavior based on the punishment of defectors. Paradoxically, the freedom to withdraw from the common enterprise leads to enforcement of social norms. Joint enterprises that are compulsory rather than voluntary are less likely to lead to cooperation.
Mosaic Organization of Neural Stem Cells in the Adult Brain
Authors: Merkle Florian T. , Mirzadeh Zaman , Alvarez-Buylla Arturo
Published: July 2007

The in vivo potential of neural stem cells in the postnatal mouse brain is not known, but because they produce many different types of neurons, they must be either very versatile or very diverse. By specifically targeting stem cells and following their progeny in vivo, we showed that postnatal stem cells in different regions produce different types of neurons, even when heterotopically grafted or grown in culture. This suggests that rather than being plastic and homogeneous, neural stem cells are a restricted and diverse population of progenitors.
Does Actin Give the Nod2 to NF-κB Activation?
Authors: Adler Elizabeth M.
Published: July 2007

Although it is best known for the structural roles its name suggests, other functions of the actin cytoskeleton have begun to emerge. For instance, in myelomonocytes and intestinal epithelial cells, disruption of the cytoskeleton leads to activation of the transcription factor NF-κB (nuclear factor κB). Nod2 is a cytoplasmic protein that signals through NF-κB to mediate an inflammatory response to bacteria. Noting that Nod2 is selectively expressed in these same two cell types, Legrand-Poels
et al
. investigated its role in the response to actin disruption. In human embryonic kidney (HEK) 293 cells cotransfected with Nod2 and an NF-κΒ reporter, disruption of the actin cytoskeleton stimulated NF-κB-mediated transcription and specifically potentiated NF-κB activation by a Nod2 ligand. Disruption of the actin cytoskeleton promoted the translocation of actin and Nod2 from detergent-insoluble to detergent-soluble cell fractions; further, immunofluorescence analysis indicated that endogenous Nod2 in HT-29 intestinal epithelial cells--as well as Nod2 expressed ectopically in various cell types--colocalized with F-actin at membrane ruffles and lamellipodia-like structures. Activated Rac1 associated with Nod2 at membrane ruffles; mutational analysis combined with immunofluorescence or coimmunoprecipitation indicated that Nod2 interacted with Rac1 through its two caspase recruitment domains (CARDs) and its leucine-rich repeats (LRRs). A dominant-negative Rac1 mutant that disrupted membrane ruffles (and did not colocalize with Nod2) stimulated NF-κB activity and potentiated NF-κB activation by Nod2. The authors propose that association of Nod2 with dynamic cytoskeletal structures induced by Rac could represent a sequestration mechanism that enables its ready mobilization in response to infection and the subsequent activation of NF-κB.

S. Legrand-Poels, G. Kustermans, F. Bex, E. Kremmer, T. A. Kufer, J. Piette, Modulation of Nod2-dependent NF-κB signaling by the actin cytoskeleton.
J. Cell Sci.
120
, 1299-1310 (2007).
[Abstract]
[Full Text]
Making Bone with Oxysterols
Authors: Gough Nancy R.
Published: July 2007

Mesenchymal cells can be directed to an osteoblastic lineage (the cells that form bone) by specific oxysterols, which are naturally occurring products of cholesterol oxidation. Dwyer
et al
. provide evidence that coapplication of 20(
S
)- and 22(
S
)-hydroxycholesterol (abbreviated SS) to pluripotent mouse marrow stromal cell line activates the expression of genes implicated in the Hedgehog pathway. Specifically, SS stimulated the genes encoding the transcription factor Gli and the receptor Patched, which are both components and targets of the Hedgehog pathway. Furthermore, SS or the Sonic hedgehog N-terminal signaling domain (ShhN) stimulated the expression of a Gli-responsive reporter gene, and this reporter gene expression was inhibited by the Smoothened inhibitor cyclopamine. Hedgehog acts at the Patched receptor, which then alleviates repression of the Smoothened transmembrane protein to stimulate Hedgehog-responsive gene expression. SS also stimulated various markers of osteoblastic differentiation, and these phenotypic changes were inhibited by cyclopamine. The effects of SS were not mediated by transcriptional stimulation of the expression of ligands of the Hedgehog pathway. SS required Smoothened, and in mouse embryo fibroblasts deficient for Smoothened, SS did not stimulate osteoblastic differentiation, although these cells retained the ability to adopt such a phenotype as bone morphogenic protein 7 did stimulate osteoblastic changes. SS apparently activates Smoothened either through a site separate from that of cyclopamine (it did not compete with cyclopamine for binding to Smoothened) or by acting indirectly to modulate Smoothened activity. Indeed, inhibition of protein kinase C activity, which had been previously implicated in the cellular response to oxysterols, blocked the SS-mediated increase in the expression of the genes encoding Gli and Patched. It remains unclear exactly how all of these pieces fit together to control the activity of the Hedgehog pathway.

J. R. Dwyer, N. Sever, M. Carlson. S. F. Nelson, P. A. Beachy, F. Parhami, Oxysterols are novel activators of the Hedgehog signaling pathway in pluripotent mesenchymal cells.
J. Biol. Chem.
282
, 8959-8968 (2007).
[Abstract]
[Full Text]
Better Without Bax?
Authors: Adler Elizabeth M.
Published: July 2007

At about age 50, depletion of ovarian follicles through apoptosis leads to the loss of cyclic ovarian function in women. Menopause, in turn, is believed to set the stage for various health problems. Although aging female mice do not undergo menopause, they experience depletion of ovarian follicles and health complications similar to those of postmenopausal women. Perez
et al
., a research group that previously showed that oocyte loss was mitigated in mice without the proapoptotic Bax, investigated the effects of
Bax
knockout on the health of aging female mice. Aging
Bax
knockout female mice (KOs) were leaner and more active than their wild-type counterparts; they retained more of their hair, developed fewer cataracts, experienced less skin wrinkling, and had stronger bones. Behavioral analyses indicated that aging KOs were less anxious than wild-type mice and had improved attention but poorer contextual memory. Whereas young KOs were less likely to become pregnant than wild-type mice, somewhat older KOs were more likely to do so. Although aged KOs failed to become pregnant, they ovulated in response to gonadotropin treatment and, when their ovarian tissue was grafted into young wild-type females, the oocytes produced viable pups. Aged KOs had reduced concentrations of serum follicle-stimulating hormone compared to wild-type mice but similar concentrations of circulating estradiol. Ovariectomy experiments indicated that the effects of Bax deficiency on bone involved both ovary-dependent and -independent mechanisms. The authors concluded that preserving ovarian function might improve quality of life in aging women.

G. I. Perez, A. Jurisicova, L. Wise, T. Lipina, M. Kanisek, A. Bechard, Y. Takai, P. Hunt, J. Roder, M. Grynpas, J. L. Tilly, Absence of the proapoptotic Bax protein extends fertility and alleviates age-related health complications in female mice.
Proc. Natl. Acad. Sci. U.S.A.
104
, 5229-5234 (2007).
[Abstract]
[Full Text]
The Trouble with Having a Big Heart
Authors: Foley John F.
Published: July 2007

When the heart is put under stress, it adapts by increasing in size, a process known as cardiac hypertrophy. After prolonged periods, however, heart failure ensues. Sano
et al
. examined the contribution that angiogenesis (the growth of new blood vessels) makes to the development of hypertrophy and cardiac failure. They established a model of hypertrophy by introducing a severe transverse aorta constriction (TAC) in mice. The resultant increase in pressure caused a gradual development of hypertrophy over 14 days, with an accompanying increase in the number of blood vessels in the heart, followed by a second phase (days 14 to 28), during which the continued pressure led to systolic dysfunction. Increased amounts of messenger RNA and protein for the angiogenic factor vascular endothelial growth factor (VEGF) were present in the TAC heart, peaking on day 14 and sharply decreasing by day 28. Hypertrophy results in ischemia (insufficient oxygen) in the myocardium, and the authors found that both the production and activity of hypoxia-inducible factor (HIF)-1α (a transcription factor that induces angiogenic factors under ischemic conditions) were stimulated in the hearts of TAC mice from days 3 to 14, returning to basal levels by day 28. The tumor suppressor p53 is known to bind to and promote the degradation of HIF-1α, and elevated amounts of p53 in the myocardium were observed 14 days after TAC. Producing TAC in p53-deficient mice resulted in higher HIF-1α activity, amounts of VEGF, and numbers of blood vessels than in wild-type mice, leading to better systolic function. This study establishes p53 as an important regulator of cardiac hypertrophy by inhibiting angiogenesis.

M. Sano, T. Minamino, H. Toko, H. Miyauchi, M. Orimo, Y. Qin, H. Akazawa, K. Tateno, Y. Kayama, M. Harada, I. Shimizu, T. Asahara, H. Hamada, S. Tomita, J. D. Molkentin, Y. Zou, I. Komuro, p53-induced inhibition of Hif-1 causes cardiac dysfunction during pressure overload.
Nature
446
, 444-448 (2007).
[PubMed]
Molecular Animation of Cell Death Mediated by the Fas Pathway
Authors: Berry Drew
Published: July 2007

This Teaching Resource includes a description and movie of the molecular events associated with apoptosis induced by the prototypic death receptor Fas. The molecules and macromolecular complexes are represented using the published structures. The movie follows the formation of the death receptor complex that causes the initial caspase activation, the release of cytochrome c from the mitochondria, and the formation of the apoptosome, and finally shows the destruction of the cytoskeleton leading to membrane blebbing. Death is initiated in a diseased cell by ligation of the Fas receptor by a killer T cell.