bluuebunny/crossref_metadata_2025 huggingface dataset:
Microscopic endonasal transsphenoidal pituitary adenomectomy in the pediatric population
Authors: Tarapore Phiroz E. , Sughrue Michael E. , Blevins Lewis , Auguste Kurtis I. , Gupta Nalin , Kunwar Sandeep
Published: December 2016

Object

Pituitary adenomas are uncommon in childhood. Although medical treatment can be effective in treating prolactinomas and some growth hormone (GH)–secreting tumors, resection is indicated when visual function is affected or the side effects of medical therapy are intolerable. The authors of this report describe their 10-year experience in managing pituitary adenomas via the microscopic endonasal transsphenoidal approach in a pediatric population.

Methods

They performed a retrospective review of a surgical case series based at a single institution and consisting of 34 consecutive pediatric patients with endocrine-active (32 patients) and endocrine-inactive (2 patients) adenomas. These patients were surgically treated via an endonasal transsphenoidal approach between 1999 and 2008. Patient charts were reviewed, and clinical data were compiled and analyzed using the chi-square and Kaplan-Meier tests.

Results

The patient cohort consisted of 20 girls and 14 boys, with ages ranging from 9 to 18 years and a median age of 16 years. Thirty-two patients (94%) underwent surgery for endocrine-active tumors, including 10 (29%) with Cushing disease, 21 (62%) with prolactinomas, and 1 (3%) with GH-secreting tumors. Two patients with nonsecreting adenomas underwent surgery for apoplexy. The mean tumor volume was 5.4 cm3, and 13 patients (38%) had suprasellar extension and 7 (21%) had cavernous sinus invasion. Gross-total resection was achieved in 26 patients (76%), although it was significantly less likely to be achieved in the setting of cavernous sinus invasion (p < 0.001) but was unaffected by suprasellar extension. Residual tumor was treated with radiation therapy in 6 patients (18%). The average duration of hospital stay was 1.6 days. The median follow-up time was 18 months. After surgery, 19 patients (56%) had normal hormone function without adjuvant therapy, 8 (24%) had normal function with adjuvant therapy, and 5 (15%) had persistently elevated hormone levels. Patients with a macroprolactinoma were significantly more likely to require postoperative adjuvant therapy than were those with a microprolactinoma (p < 0.03).

Conclusions

Endonasal transsphenoidal resection is a safe, well-tolerated, and potentially curative treatment option for pituitary adenomas in children. Despite the technical challenges associated with this approach in the pediatric population, these tumors can be effectively managed with minimal morbidity. Endocrine function is usually preserved, and the majority of patients will not require lifelong medical therapy.
Pilomyxoid astrocytoma of the cerebellum
Authors: Ajani Olufemi A. , Sulaiti Ghanem Al , Bozom Issam Al
Published: December 2016

Pilomyxoid astrocytomas (PMAs) are low-grade (WHO Grade II) tumors for which the imaging features are similar to pilocytic astrocytomas (PAs), but for which histological features and the clinical course differ. They are classified as a variant of PA. They have only been recently recognized, and they behave more aggressively than PAs. Most cases occur in the hypothalamic-chiasmatic area, although they may be located in any part of the neuraxis. Posterior fossa PMAs are very rare. The authors report a case of a 2-year-old girl with cerebellar PMA.
Use of occipital bone graft in pediatric posterior cervical fusion: an alternative paramedian technique and review of the literature
Authors: Bauman Joel A. , Hardesty Douglas A. , Heuer Gregory G. , Storm Phillip B.
Published: December 2016

An alternative method of bone grafting for pediatric posterior cervical and occipitocervical fixation is presented in detail. Full-thickness autografts from small craniectomies of the occipital bone are used to augment posterior segmental fusion in pediatric patients. Twelve patients have been treated successfully without bone graft donor site complications. The technical differences from previously reported uses of calvarial autograft in spine fusion are reviewed.
Regression of recurrent glioblastoma infiltrating the brainstem after convection-enhanced delivery of nimustine hydrochloride
Authors: Saito Ryuta , Sonoda Yukihiko , Kumabe Toshihiro , Nagamatsu Ken-ichi , Watanabe Mika , Tominaga Teiji
Published: December 2016

This 13-year-old boy with a history of cranial irradiation for the CNS recurrence of acute lymphocytic leukemia developed a glioblastoma in the right cerebellum. Resection and chemo- and radiotherapy induced remission of the disease. However, recurrence was noted in the brainstem region 8 months later. Because no effective treatment was available for this recurrent lesion, the authors decided to use convection-enhanced delivery (CED) to infuse nimustine hydrochloride. On stereotactic insertion of the infusion cannula into the brainstem lesion, CED of nimustine hydrochloride was performed with real-time MR imaging to monitor the co-infused chelated gadolinium. The patient's preinfusion symptom of diplopia disappeared after treatment. Follow-up MR imaging revealed the response of the tumor. The authors report on a case of recurrent glioblastoma infiltrating the brainstem that regressed after CED of nimustine hydrochloride.
Short- and long-term effects of selective dorsal rhizotomy on gross motor function in ambulatory children with spastic diplegia
Authors: van Schie Petra E. M. , Schothorst Maaike , Dallmeijer Annet J. , Vermeulen R. Jeroen , van Ouwerkerk Willem J. R. , Strijers Rob L. M. , Becher Jules G.
Published: December 2016

Object

The primary aim of this prospective cohort study was to evaluate the short-term (1 year) and long-term (mean 6 years) effects of selective dorsal rhizotomy (SDR) on gross motor function and spasticity in ambulatory children with spastic diplegia. Secondary aims were to investigate side effects, additional treatment during follow-up (botulinum toxin type A injections or orthopedic surgery), and parental satisfaction.

Methods

Thirty-three children who had undergone SDR at a mean age of 6 years and 7 months (± 2 years) were included. There were 7 children at Gross Motor Function Classification System (GMFCS) Level I, 7 at Level II, and 19 at Level III. Gross motor function was assessed with the Gross Motor Function Measure–66 (GMFM-66). Spasticity was measured according to a modified Tardieu scale. Side effects, additional treatment, and parental satisfaction were recorded using a parental questionnaire and medical records.

Results

At 1-year follow-up, mean GMFM-66 scores improved significantly by 4.3 ± 4.1 points. Children at GMFCS Levels I and II showed significantly more improvement (7.2 points) on the GMFM-66 compared with children at GMFCS Level III (2.9 points). On long-term follow-up (mean 6 years ± 22 months), mean GMFM-66 scores improved significantly by 6.5 ± 5.9 points, without a difference between children at GMFCS Levels I and II and Level III. No relapse of spasticity was noted. Ten children (30%) needed orthopedic surgery and 13 children (39%) received botulinum toxin type A treatment after SDR. Twenty (91%) of the 22 parents who answered the questionnaire at long-term follow-up believed that their child's functioning had improved after SDR.

Conclusions

Selective dorsal rhizotomy resulted in short- and long-term improvements in gross motor function, without relapse of spasticity. However, the majority of the children still needed additional surgery or botulinum toxin A treatment.
Rapid online language mapping with electrocorticography
Authors: Miller Kai J. , Abel Taylor J. , Hebb Adam O. , Ojemann Jeffrey G.
Published: December 2016

Object

Emerging research in evoked broadband electrocorticographic (ECoG) measurement from the cortical surface suggests that it might cleanly delineate the functional organization of cortex. The authors sought to demonstrate whether this could be done in a same-session, online manner to identify receptive and expressive language areas.

Methods

The authors assessed the efficacy of simple integration of “χ-band” (76–200 Hz) change in the ECoG signal by implementing a simple band-pass filter to estimate broadband spectral change. Following a brief (less than 10-second) period to characterize baseline activity, χ-band activity was integrated while 7 epileptic patients with implanted ECoG electrodes performed a verb-generation task.

Results

While the patients were performing verb-generation or noun-reading tasks, cortical activation was consistently identified in primary mouth motor area, superior temporal gyrus, and Broca and Wernicke association areas. Maps were robust after a mean time of 47seconds (using an “activation overlap” measure). Correlation with electrocortical stimulation was not complete and was stronger for noun reading than verb generation.

Conclusions

Broadband ECoG changes can be captured online to identify eloquent cortex. This demonstrates the existence of a powerful new tool for functional mapping in the operative and chronic implant setting.
Treatment of a malignant peripheral nerve sheath tumor and its complications through a multidisciplinary approach
Authors: McLaughlin Eamon J. , Heuer Gregory G. , Whitmore Robert G. , Birknes John K. , Belasco Jean , Sterman Daniel , Low David W. , Storm Phillip B.
Published: December 2016

The authors report the case of a 14-year-old girl with a residual malignant peripheral nerve sheath tumor after thoracotomy, chemotherapy, and radiation therapy. The residual tumor, which involved the intercostal muscles, aorta, and neural foramina of T4–10, was completely resected through a costotransversectomy and multiple hemilaminotomies with the patient in the prone position and was stabilized using a T1–12 pedicle screw fusion. Postoperatively, the patient developed several infections requiring multiple washouts and prolonged antibiotics. Thirty months after surgery, she developed a bronchocutaneous fistula. The hardware was removed, and a vascularized latissimus dorsi free flap was placed over the lung. She continued to have an air leak and presented 3 weeks later with a 40° left thoracic curve. She returned to the operating room for a T2–L2 fusion with a vascularized fibular graft. On postoperative Day 1, she underwent a bronchoscopy and had her left lower lobe airways occluded with multiple novel one-way endobronchial valves. She is now 5 years out from her tumor resection and 3 years out from her definitive fusion. She has no evidence of residual tumor, infection, or pseudarthrosis and continues to remain asymptomatic.
Level I to III craniofacial approaches based on Barrow classification for treatment of skull base meningiomas: surgical technique, microsurgical anatomy, and case illustrations
Authors: Avcı Emel , Aktüre Erinç , Seçkin Hakan , Uluç Kutluay , Bauer Andrew M. , Izci Yusuf , Morcos Jacques J. , Başkaya Mustafa K.
Published: December 2016

Object

Although craniofacial approaches to the midline skull base have been defined and surgical results have been published, clear descriptions of these complex approaches in a step-wise manner are lacking. The objective of this study is to demonstrate the surgical technique of craniofacial approaches based on Barrow classification (Levels I–III) and to study the microsurgical anatomy pertinent to these complex craniofacial approaches.

Methods

Ten adult cadaveric heads perfused with colored silicone and 24 dry human skulls were used to study the microsurgical anatomy and to demonstrate craniofacial approaches in a step-wise manner. In addition to cadaveric studies, case illustrations of anterior skull base meningiomas were presented to demonstrate the clinical application of the first 3 (Levels I–III) approaches.

Results

Cadaveric head dissection was performed in 10 heads using craniofacial approaches. Ethmoid and sphenoid sinuses, cribriform plate, orbit, planum sphenoidale, clivus, sellar, and parasellar regions were shown at Levels I, II, and III. In 24 human dry skulls (48 sides), a supraorbital notch (85.4%) was observed more frequently than the supraorbital foramen (14.6%). The mean distance between the supraorbital foramen notch to the midline was 21.9 mm on the right side and 21.8 mm on the left. By accepting the middle point of the nasofrontal suture as a landmark, the mean distances to the anterior ethmoidal foramen from the middle point of this suture were 32 mm on the right side and 34 mm on the left. The mean distance between the anterior and posterior ethmoidal foramina was 12.3 mm on both sides; the mean distance between the posterior ethmoidal foramen and distal opening of the optic canal was 7.1 mm on the right side and 7.3 mm on the left.

Conclusions

Barrow classification is a simple and stepwise system to better understand the surgical anatomy and refine the techniques in performing these complex craniofacial approaches. On the other hand, thorough anatomical knowledge of the midline skull base and variations of the neurovascular structures is crucial to perform successful craniofacial approaches.
Surgical nuances for removal of tuberculum sellae meningiomas with optic canal involvement using the endoscopic endonasal extended transsphenoidal transplanum transtuberculum approach
Authors: Liu James K. , Christiano Lana D. , Patel Smruti K. , Tubbs R. Shane , Eloy Jean Anderson
Published: December 2016

Tuberculum sellae meningiomas frequently extend into the optic canals. Radical tumor resection including the involved dural attachment, underlying hyperostotic bone, and intracanalicular tumor in the optic canal offers the best chance of a Simpson Grade I resection to minimize recurrence. Decompression of the optic canal with removal of the intracanalicular tumor also improves visual outcome since this portion of the tumor is usually the cause of asymmetrical visual loss.

The purely endoscopic endonasal extended transsphenoidal approach offers a direct midline trajectory and immediate access to tuberculum sellae meningiomas without brain retraction and manipulation of neurovascular structures. Although the endoscopic approach has been previously criticized for its inability to remove tumor within the optic canals, complete Simpson Grade I tumor removal including intracanalicular tumor, dural attachment, and involved hyperostotic bone can be achieved in properly selected patients. Excellent visualization of the suprasellar region and the inferomedial aspects of both optic canals allows for extracapsular, extraarachnoid dissection of the tumor from the critical structures using bimanual microsurgical dissection.

In this report, the authors describe the operative nuances for removal of tuberculum sellae meningiomas with optic canal involvement using a purely endoscopic endonasal extended transsphenoidal (transplanum transtuberculum) approach. They specifically highlight the technique for endonasal bilateral optic nerve decompression and removal of intracanalicular tumor to improve postoperative visual function, as demonstrated in 2 illustrative cases. Special attention is also given to cranial base reconstruction to prevent CSF leakage using the vascularized pedicled nasoseptal flap.
Instruction Sequence Size Complexity of Parity
Authors: Bergstra J.A. , Middelburg C.A.
Published: December 2016

Each Boolean function can be computed by a single-pass instruction sequence that contains only instructions to set and get the content of Boolean registers, forward jump instructions, and a termination instruction. Auxiliary Boolean registers are not necessary for this. In the current paper, we show that, in the case of the parity functions, shorter instruction sequences are possible with the use of an auxiliary Boolean register in the presence of instructions to complement the content of auxiliary Boolean registers. This result supports, in a setting where programs are instruction sequences acting on Boolean registers, a basic intuition behind the storage of auxiliary data, namely the intuition that this makes possible a reduction of the size of a program. The work presented in this paper is carried out in the setting of PGA (ProGram Algebra)
Hemodynamic and autonomic responses after a single session of resistance exercise following anodal motor cortex tDCS
Authors: Germano-Soares Antonio H. , Montenegro Rafael A. , Cavalcante Bruno R. , Domingues Wagner J.R. , de Lima Paulo F.M. , Menêses Annelise L. , Almeida Tarciso R.M. , Okano Alexandre H. , Ritti-Dias Raphael M.
Published: December 2016

BACKGROUND:

Transcranial direct current stimulation (tDCS) seems to modulate cardiac autonomic function and blood pressure (BP) at rest and during exercise. Therefore, it is possible that anodal tDCS could influence post-exercise hypotension.

OBJECTIVE:

To investigate whether anodal tDCS applied over the motor cortex would affect cardiac autonomic modulation and BP after resistance exercise.

METHODS:

Twelve apparently healthy young men performed two experimental sessions: anodal tDCS or sham condition followed by resistance exercise. Blood pressure (BP), heart rate (HR), rate-pressure product (RPP), and HR variability (HRV) were obtained before and during post-exercise recovery (at 20 and 60 minutes).

RESULTS:

Compared to pre-exercise, systolic BP decreased at 20 and at 60 minutes of post-exercise recovery only in anodal tDCS condition(p = 0.03), with no statistical differences in sham condition (p > 0.05). Diastolic and mean BP reduced after both anodal tDCS and sham conditions with no differences between them (P> 0.05). In comparison with anodal tDCS, there were slower HR recovery (tDCS vs. sham: -2 ± 14 vs. 14 ± 8 bpm) and higher RPP (tDCS vs. sham: -1083 ± 1846 vs. 1672 ± 1275 mmHg × bpm) after exercise following sham condition (P< 0.01). No differences were found in any of the HRV analyzed parameters (P> 0.05).

CONCLUSION:

A single session of primary motor cortex tDCS is capable of decreasing the systolic BP and HR responses, as well as the cardiac work after a resistance exercise session in young normotensive subjects regardless of any changes in cardiac autonomic modulation.
Gastrocnemius muscle activation during plantar flexion with different feet positioning in physically active young men
Authors: Marcori Alexandre J. , Moura Túlio B.M.A. , Okazaki Victor H.A.
Published: December 2016

BACKGROUND:

Varying exercise parameters, such as angles of movement, can cause different activation patterns within muscle compartments. Therefore, it is expected that feet positioning variations could influence gastrocnemius activity.

OBJECTIVE:

Compare gastrocnemius activation during plantar flexion with feet pointing forwards (FO), inwards (IN) and outwards (OU).

METHODS:

Sixteen physically active men (21 ± 2 years; 1.75 ± 0.06 meters and 74.8 ± 7.2 kg), performed 3 sets of 10 repetitions in each of the following experimental conditions: plantar flexion with feet pointing FO, IN and OU. The root mean square (RMS) of the muscular activation of both gastrocnemius heads was analyzed in each set by electromyography.

RESULTS:

For the medial head of the gastrocnemius, the OU condition presented greater RMS values when compared to the IN (z = 3.41; p < 0.001) and FO (z = 2.37; p≤ 0.017) conditions. For the lateral head, however, the IN condition demonstrated greatest RMS when compared with OU (z = 3.20; p = 0.001) and FO (z = 3.25; p = 0.001) conditions.

CONCLUSIONS:

These results suggest that it is possible to create greater activation sites in the gastrocnemius. Trainers and practitioners could use this to prescribe exercise more efficiently, possibly correcting asymmetries in athletes, especially bodybuilders.
Fundamental properties of high-quality carbon nanofoam: from low to high density
Authors: Frese Natalie , Taylor Mitchell Shelby , Neumann Christof , Bowers Amanda , Gölzhäuser Armin , Sattler Klaus
Published: December 2016

Highly uniform samples of carbon nanofoam from hydrothermal sucrose carbonization were studied by helium ion microscopy (HIM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Foams with different densities were produced by changing the process temperature in the autoclave reactor. This work illustrates how the geometrical structure, electron core levels, and the vibrational signatures change when the density of the foams is varied. We find that the low-density foams have very uniform structure consisting of micropearls with ≈2–3 μm average diameter. Higher density foams contain larger-sized micropearls (≈6–9 μm diameter) which often coalesced to form nonspherical μm-sized units. Both, low- and high-density foams are comprised of predominantly sp2-type carbon. The higher density foams, however, show an advanced graphitization degree and a stronger sp3-type electronic contribution, related to the inclusion of sp3 connections in their surface network.
Biochemical and structural characterisation of the second oxidative crosslinking step during the biosynthesis of the glycopeptide antibiotic A47934
Authors: Ulrich Veronika , Brieke Clara , Cryle Max J
Published: December 2016

The chemical complexity and biological activity of the glycopeptide antibiotics (GPAs) stems from their unique crosslinked structure, which is generated by the actions of cytochrome P450 (Oxy) enzymes that affect the crosslinking of aromatic side chains of amino acid residues contained within the GPA heptapeptide precursor. Given the crucial role peptide cyclisation plays in GPA activity, the characterisation of this process is of great importance in understanding the biosynthesis of these important antibiotics. Here, we report the cyclisation activity and crystal structure of StaF, the D-O-E ring forming Oxy enzyme from A47934 biosynthesis. Our results show that the specificity of StaF is reduced when compared to Oxy enzymes catalysing C-O-D ring formation and that this activity relies on interactions with the non-ribosomal peptide synthetase via the X-domain. Despite the interaction of StaF with the A47934 X-domain being weaker than for the preceding Oxy enzyme StaH, StaF retains higher levels of in vitro activity: we postulate that this is due to the ability of the StaF/X-domain complex to allow substrate reorganisation after initial complex formation has occurred. These results highlight the importance of testing different peptide/protein carrier constructs for in vitro GPA cyclisation assays and show that different Oxy homologues can display significantly different catalytic propensities despite their overall similarities.
PROBING WHIM AROUND GALAXY CLUSTERS WITH FAST RADIO BURSTS AND THE SUNYAEV–ZEL’DOVICH EFFECT
Authors: Fujita Yutaka , Akahori Takuya , Umetsu Keiichi , Sarazin Craig L. , Wong Ka-Wah
Published: December 2016

We propose a new method to probe the warm hot intergalactic medium (WHIM) beyond the virial radius (R
200) of a cluster of galaxies, where X-ray observations are not easily achievable. In this method, we use dispersion measures (DMs) of fast radio bursts (FRBs) that appear behind the cluster and the Sunyaev–Zel’dovich (SZ) effect toward the cluster. The DMs reflect the density of the intracluster medium including the WHIM. If we observe a sufficient number of FRBs in the direction of the cluster, we can derive the density profile from the DMs. Similarly, we can derive the pressure profile from the SZ effect. By combining the density and the pressure profiles, the temperature profile can be obtained. Based on mock observations of nearby clusters, we find that the density of the WHIM will be determined even at

from the cluster center when FRB observations with the Square Kilometre Array become available. The temperature can be derived out to

, and the radius is limited by the current sensitivity of SZ observations.
GIANT CORONAL LOOPS DOMINATE THE QUIESCENT X-RAY EMISSION IN RAPIDLY ROTATING M STARS
Authors: Cohen O. , Yadav R. , Garraffo C. , Saar S. H. , Wolk S. J. , Kashyap V. L. , Drake J. J. , Pillitteri I.
Published: December 2016

Observations indicate that magnetic fields in rapidly rotating stars are very strong, on both small and large scales. What is the nature of the resulting corona? Here we seek to shed some light on this question. We use the results of an anelastic dynamo simulation of a rapidly rotating fully convective M star to drive a physics-based model for the stellar corona. We find that due to the several kilo Gauss large-scale magnetic fields at high latitudes, the corona, and its X-ray emission are dominated by star-size large hot loops, while the smaller, underlying colder loops are not visible much in the X-ray. Based on this result, we propose that, in rapidly rotating stars, emission from such coronal structures dominates the quiescent, cooler but saturated X-ray emission.
THE BURRELL SCHMIDT DEEP VIRGO SURVEY: TIDAL DEBRIS, GALAXY HALOS, AND DIFFUSE INTRACLUSTER LIGHT IN THE VIRGO CLUSTER
Authors: Mihos J. Christopher , Harding Paul , Feldmeier John J. , Rudick Craig , Janowiecki Steven , Morrison Heather , Slater Colin , Watkins Aaron
Published: December 2016

We present the results of a deep imaging survey of the Virgo cluster of galaxies, concentrated around the cores of Virgo subclusters A and B. The goal of this survey was to detect and study very low surface brightness features present in Virgo, including discrete tidal features, the faint halos of luminous galaxies, and the diffuse intracluster light (ICL). Our observations span roughly 16 degrees2 in two filters, reaching a 3σ limiting depth of

 = 29.5 and

 = 28.5 mag arcsec−2. At these depths, our limiting systematic uncertainties are astrophysical: variations in faint background sources as well as scattered light from galactic dust. We show that this dust-scattered light is well traced by deep far-infrared imaging, making it possible to separate it from true diffuse light in Virgo. We use our imaging to trace and measure the color of the diffuse tidal streams and ICL in the Virgo core near M87, in fields adjacent to the core including the M86/M84 region, and to the south of the core around M49 and subcluster B, along with the more distant W

cloud around NGC 4365. Overall, the bulk of the projected ICL is found in the Virgo core and within the W

cloud; we find little evidence for an extensive ICL component in the field around M49. The bulk of the ICL we detect is fairly red in color (B − V = 0.7–0.9), indicative of old, evolved stellar populations. Based on the luminosity of the observed ICL features in the cluster, we estimate a total Virgo ICL fraction of 7%–15%. This value is somewhat smaller than that expected for massive, evolved clusters, suggesting that Virgo is still in the process of growing its extended ICL component. We also trace the shape of M87's extremely boxy outer halo out to ∼150 kpc, and show that the current tidal stripping rate from low luminosity galaxies is insufficient to have built M87's outer halo over a Hubble time. We identify a number of previously unknown low surface brightness structures around galaxies projected close to M86 and M84. The extensive diffuse light seen in the infalling W

cloud around NGC 4365 is likely to be subsumed in the general Virgo ICL component once the group enters the cluster, illustrating the importance of group infall in generating ICL. Finally, we also identify another large and extremely low surface brightness ultradiffuse galaxy, likely in the process of being shredded by the cluster tidal field. With the survey complete, the full imaging data set is now available for public release.
MOSFIRE SPECTROSCOPY OF QUIESCENT GALAXIES AT 1.5 < z < 2.5. I. EVOLUTION OF STRUCTURAL AND DYNAMICAL PROPERTIES
Authors: Belli Sirio , Newman Andrew B. , Ellis Richard S.
Published: December 2016

We present deep near-infrared spectra for a sample of 24 quiescent galaxies in the redshift range

obtained with the MOSFIRE spectrograph at the W. M. Keck Observatory. In conjunction with a similar data set we obtained in the range

with the LRIS spectrograph, we analyze the kinematic and structural properties for 80 quiescent galaxies, the largest homogeneously selected sample to date spanning 3 Gyr of early cosmic history. Analysis of our Keck spectra together with measurements derived from associated Hubble Space Telescope images reveals increasingly larger stellar velocity dispersions and smaller sizes to redshifts beyond

. By classifying our sample according to Sérsic indices, we find that among disk-like systems the flatter ones show a higher dynamical to stellar mass ratio compared to their rounder counterparts, which we interpret as evidence for a significant contribution of rotational motion. For this subset of disk-like systems, we estimate that

, the ratio of the circular velocity to the intrinsic velocity dispersion, is a factor of two larger than for present-day disky quiescent galaxies. We use the velocity dispersion measurements also to explore the redshift evolution of the dynamical to stellar mass ratio, and to measure for the first time the physical size growth rate of individual systems over two distinct redshift ranges, finding a faster evolution at earlier times. We discuss the physical origin of this time-dependent growth in size in the context of the associated reduction of the systematic rotation.
THE ACCRETION RATE DEPENDENCE OF BURST OSCILLATION AMPLITUDE
Authors: Ootes Laura S. , Watts Anna L. , Galloway Duncan K. , Wijnands Rudy
Published: December 2016

Neutron stars in low-mass X-ray binaries exhibit oscillations during thermonuclear bursts, attributed to asymmetric brightness patterns on the burning surfaces. All models that have been proposed to explain the origin of these asymmetries (spreading hotspots, surface waves, and cooling wakes) depend on the accretion rate. By analysis of archival RXTE data of six oscillation sources, we investigate the accretion rate dependence of the amplitude of burst oscillations. This more than doubles the size of the sample analyzed previously by Muno et al., who found indications for a relationship between accretion rate and oscillation amplitudes. We find that burst oscillation signals can be detected at all observed accretion rates. Moreover, oscillations at low accretion rates are found to have relatively small amplitudes (

) while oscillations detected in bursts observed at high accretion rates cover a broad spread in amplitudes (

). In this paper we present the results of our analysis and discuss these in the light of current burst oscillation models. Additionally, we investigate the bursts of two sources without previously detected oscillations. Despite the fact that these sources have been observed at accretion rates where burst oscillations might be expected, we find their behavior not to be anomalous compared to oscillation sources.
FOLLOWING THE COSMIC EVOLUTION OF PRISTINE GAS. I. IMPLICATIONS FOR MILKY WAY HALO STARS
Authors: Sarmento Richard , Scannapieco Evan , Pan Liubin
Published: December 2016

We make use of a new subgrid model of turbulent mixing to accurately follow the cosmological evolution of the first stars, the mixing of their supernova (SN) ejecta, and the impact on the chemical composition of the Galactic Halo. Using the cosmological adaptive mesh refinement code ramses, we implement a model for the pollution of pristine gas as described in Pan et al. Tracking the metallicity of Pop III stars with metallicities below a critical value allows us to account for the fraction of

stars formed even in regions in which the gas’s average metallicity is well above

We demonstrate that such partially mixed regions account for 0.5 to 0.7 of all Pop III stars formed up to z = 5. Additionally, we track the creation and transport of “primordial metals” (PM) generated by Pop III SNe. These neutron-capture deficient metals are taken up by second-generation stars and likely lead to unique abundance signatures characteristic of carbon-enhanced, metal-poor (CEMP-no) stars. As an illustrative example, we associate primordial metals with abundance ratios used by Keller et al. to explain the source of metals in the star SMSS J031300.36-670839.3, finding good agreement with the observed [Fe/H], [C/H], [O/H], and [Mg/Ca] ratios in CEMP-no Milky Way halo stars. Similar future simulations will aid in further constraining the properties of Pop III stars using CEMP observations, as well as improve predictions of the spatial distribution of Pop III stars, as will be explored by the next generation of ground- and space-based telescopes.
ZEEMAN DOPPLER MAPS: ALWAYS UNIQUE, NEVER SPURIOUS?
Authors: Stift Martin J. , Leone Francesco
Published: December 2016

Numerical models of atomic diffusion in magnetic atmospheres of ApBp stars predict abundance structures that differ from the empirical maps derived with (Zeeman) Doppler mapping (ZDM). An in-depth analysis of this apparent disagreement investigates the detectability by means of ZDM of a variety of abundance structures, including (warped) rings predicted by theory, but also complex spot-like structures. Even when spectra of high signal-to-noise ratio are available, it can prove difficult or altogether impossible to correctly recover shapes, positions, and abundances of a mere handful of spots, notwithstanding the use of all four Stokes parameters and an exactly known field geometry; the recovery of (warped) rings can be equally challenging. Inversions of complex abundance maps that are based on just one or two spectral lines usually permit multiple solutions. It turns out that it can by no means be guaranteed that any of the regularization functions in general use for ZDM (maximum entropy or Tikhonov) will lead to a true abundance map instead of some spurious one. Attention is drawn to the need for a study that would elucidate the relation between the stratified, field-dependent abundance structures predicted by diffusion theory on the one hand, and empirical maps obtained by means of “canonical” ZDM, i.e., with mean atmospheres and unstratified abundances, on the other hand. Finally, we point out difficulties arising from the three-dimensional nature of the atomic diffusion process in magnetic ApBp star atmospheres.
FIRST DETECTION OF CHROMOSPHERIC MAGNETIC FIELD CHANGES DURING AN X1-FLARE
Authors: Kleint Lucia
Published: December 2016

Stepwise changes of the photospheric magnetic field, which often becomes more horizontal, have been observed during many flares. Previous interpretations include coronal loops that contract, and it has been speculated that such jerks could be responsible for sunquakes. Here we report the detection of stepwise chromospheric line-of-sight magnetic field (B

) changes obtained through spectropolarimetry of Ca ii 8542 Å with DST/IBIS during the X1-flare SOL20140329T17:48. These changes are stronger (<640 Mx cm−2) and appear in larger areas than their photospheric counterparts (<320 Mx cm−2). The absolute value of

more often decreases than increases. Photospheric changes are predominantly located near a polarity inversion line, and chromospheric changes near the footpoints of loops. The locations of changes are near, but not exactly co-spatial to hard X-ray emission and neither to enhanced continuum emission nor to a small sunquake. Enhanced chromospheric and coronal emission is observed in nearly all locations that exhibit changes of

, but the emission also occurs in many locations without any

changes. Photospheric and chromospheric changes of

show differences in timing, sign, and size and seem independent of each other. A simple model of contracting loops yields changes of the opposite sign to those observed. An explanation for this discrepancy could be increasing loop sizes or loops that untwist in a certain direction during the flare. It is yet unclear which processes are responsible for the observed changes and their timing, size, and location, especially considering the incoherence between the photosphere and the chromosphere.
THE RELATIONSHIP BETWEEN MONO-ABUNDANCE AND MONO-AGE STELLAR POPULATIONS IN THE MILKY WAY DISK
Authors: Minchev I. , Steinmetz M. , Chiappini C. , Martig M. , Anders F. , Matijevic G. , Jong R. S. de
Published: December 2016

Studying the Milky Way disk structure using stars in narrow bins of [Fe/H] and [α/Fe] has recently been proposed as a powerful method to understand the Galactic thick and thin disk formation. It has been assumed so far that these mono-abundance populations (MAPs) are also coeval, or mono-age, populations. Here we study this relationship for a Milky Way chemodynamical model and show that equivalence between MAPs and mono-age populations exists only for the high-[α/Fe] tail, where the chemical evolution curves of different Galactic radii are far apart. At lower [α/Fe]-values an MAP is composed of stars with a range in ages, even for small observational uncertainties and a small MAP bin size. Due to the disk inside-out formation, for these MAPs younger stars are typically located at larger radii, which results in negative radial age gradients that can be as large as 2 Gyr kpc−1. Positive radial age gradients can result for MAPs at the lowest [α/Fe] and highest [Fe/H] end. Such variations with age prevent the simple interpretation of observations for which accurate ages are not available. Studying the variation with radius of the stellar surface density and scale height in our model, we find good agreement to recent analyses of the APOGEE red-clump (RC) sample when 1–4 Gyr old stars dominate (as expected for the RC). Our results suggest that the APOGEE data are consistent with a Milky Way model for which mono-age populations flare for all ages. We propose observational tests for the validity of our predictions and argue that using accurate age measurements, such as from asteroseismology, is crucial for putting constraints on Galactic formation and evolution.
Pratiques scolaires et genre dans les écoles primaires à Cotonou
Authors: Gastineau Bénédicte , Gnele Josette , Mizochounnou Saturnine
Published: December 2016

Depuis 2000, le Bénin a mis en œuvre un ensemble de politiques et de programmes d’éducation qui ont permis d’améliorer la scolarisation des enfants à l’école primaire, particulièrement celle des filles. Aujourd’hui à Cotonou, la parité fille-garçon y est atteinte. Pour autant, comme cet article le montre, le traitement des filles et des garçons n’est pas le même. Les auteurs s’appuient sur des données qualitatives issues de l’observation de sessions de cours et de 26 entretiens approfondis auprès d’enseignant-e-s et directeurs et directrices de deux écoles de Cotonou. Les analyses de ces données montrent que les représentations des enseignant-e-s sur les qualités des enfants selon leur sexe influencent les interactions entre maîtres et élèves, et orientent la pédagogie. Le placement des élèves dans la classe, les prises de parole, le partage des tâches et des responsabilisés sont ainsi fortement liés aux normes de genre. Une telle situation tend à conforter les distinctions et les inégalités entre les filles et les garçons, observées en dehors de l’école.
Stratégies reproductives à Ouagadougou
Authors: Bougma Moussa , Lange Marie-France , Legrand Thomas K. , Kobiané Jean-François
Published: December 2016

De nombreuses études quantitatives conduites récemment en Afrique subsaharienne mettent en évidence une corrélation négative entre le nombre d’enfants et leur scolarisation, mais les mécanismes à l’origine d’une telle relation restent méconnus. Cette étude utilise des données qualitatives produites par l’Observatoire de population de Ouagadougou pour explorer le rôle de la scolarisation des enfants dans les stratégies reproductives de leurs parents. Des entretiens semi-directifs et approfondis ont permis d’examiner les perceptions des femmes et des hommes sur les coûts et bénéfices de l’éducation de leur progéniture et de comprendre dans quelle mesure celles-ci entrent en compte dans leurs stratégies reproductives. Le discours des participants à l’enquête indique que cette relation négative entre le nombre d’enfants et leur scolarisation dans les quartiers périphériques de Ouagadougou est intimement liée aux changements dans ces coûts et bénéfices. L’article montre ainsi que les dépenses scolaires reposent dorénavant de façon presque exclusive sur les parents biologiques.
Baisse de la fécondité dans un contexte d’amélioration du statut des femmes ?
Authors: Lebugle Mojdehi Amandine
Published: December 2016

La forte baisse de la fécondité observée en milieu rural iranien dans la seconde moitié du xx e siècle interroge. Comment, dans un contexte d’isolement international, de prédominance de la religion, les populations rurales ont-elles réduit leur fécondité ? Pour y répondre, la question du statut des femmes est posée : a-t-on assisté à une meilleure égalité entre les sexes ? La baisse de la fécondité est-elle survenue alors que le déséquilibre des sexes prévaut toujours ? Trois dimensions du statut de la femme sont mobilisées ici : l’éducation, le travail et, au sein de la famille, l’entrée en vie maritale et la pratique contraceptive. S’appuyant sur des données de recensements, d’enquêtes socio-démographiques et d’une enquête de terrain, l’étude se focalise sur la société rurale, là où les transformations ont été les plus spectaculaires de par leur ampleur et leur rapidité.
Le développement durable selon une entreprise d’exploitation forestière au nord-est du Gabon
Authors: Bourel Étienne
Published: December 2016

Dans la région de l’Ogooué-Ivindo, au nord-est du Gabon, l’exploitation industrielle de la forêt est récente. Cet article analyse, en termes de gouvernementalité, la configuration de pouvoir bâtie par et autour de la filière bois d’une entreprise multinationale d’agroalimentaire. Dirigée par des Indiens, basée à Singapour et présente au Gabon en accord avec le régime politique national, son implantation locale modèle la vie des personnes vivant sur le terrain.
Immigration et statistiques en Guyane
Authors: Cambrézy Luc
Published: December 2016

Le département français de la Guyane se caractérise par une forte immigration dont le poids joue un rôle considérable dans l’évolution et la structure de la population. Mais les statistiques accessibles sur le sujet sont peu nombreuses, très formatées, et se révèlent à l’analyse difficiles à croiser et à interpréter. Plus grave, elles sont souvent peu fiables du fait de l’importance de la population « clandestine » mais aussi de la manière dont l’Institut national de la statistique et des études économiques (Insee) opère une distinction entre populations française et étrangère. Comme en écho à la perception floue sinon tronquée de la question migratoire, la population guyanaise est elle-même fortement segmentée par l’importante diversité ethnique et culturelle (Amérindiens, Noirs-marrons, Créoles, etc.). Ce « flou démographique » est au fond à l’image du caractère composite de la société guyanaise. Mais il en traduit aussi les ambiguïtés dans un contexte où l’immigration constitue la toile de fond des diverses revendications d’autochtonie qui s’expriment et qui interrogent sur l’identité guyanaise, ou ce que d’aucuns nomment encore la « guyanité ». Comprendre comment la mesure des phénomènes migratoires s’en trouve affectée permet de mieux appréhender cette réalité complexe.
L’accès à l’emploi à Lubumbashi
Authors: Kahola Tabu Olivier
Published: December 2016

Dans un contexte socio-économique où il y a pléthore d’individus qualifiés et/ou l’offre d’emploi est insuffisante, chaque opportunité de travail est une source d’enjeux et de compétition. En République démocratique du Congo (RDC), afin de réussir leur insertion professionnelle, les demandeurs d’emploi tendent à plus mobiliser les logiques informelles que formelles. Celles-ci consistent à utiliser le capital social et économique des parents, manipuler les sociabilités partisanes, intégrer les réseaux d’hommes politiques, recourir aux pratiques occultes, avoir le sens de l’opportunisme, etc. Sans un réseau de connaissances et d’appuis sûrs, l’accès à l’emploi salarié apparaît bien difficile pour les jeunes diplômés de Lubumbashi.
South Africa in African agriculture : Investment models and their dynamics towards a structured conquest
Authors: Anseeuw Ward , Boche Mathieu
Published: December 2016

Le capital agraire et entrepreneurial de l’Afrique du Sud investit aujourd’hui dans l’agriculture de 28 pays africains, à travers les exportations de ses agriculteurs, son agroindustrie en amont et en aval, et son expertise technique et de gestion. Ces investissements sont souvent soutenus par le gouvernement sud-africain, à travers des traités bilatéraux d’investissement et des accords commerciaux préférentiels. Cet article présente, sur la base d’un travail empirique approfondi, différents modèles selon lesquels l’Afrique du Sud est en train de conquérir le secteur agricole sur le continent, faisant valoir qu’il n’y a pas de « modèle sud-africain unique ». Il évalue également la dynamique et l’évolution de ces investissements, en précisant le nombre élevé des échecs, leur besoin de s’intégrer verticalement et la manière dont une dynamique plus organisée se structure actuellement. Bien qu’il semble que la présence sud-africaine sur le continent soit là pour durer, l’article remet en question ses implications réelles globales pour la transformation agraire de l’Afrique.
Coopération et investissement brésiliens au Mozambique : une complémentarité contestée
Authors: Nogueira Isabela , Ollinaho Ossi
Published: December 2016

Tandis qu’il devenait le plus grand investisseur étranger au Mozambique, le Brésil a établi ces dernières années plusieurs programmes de développement sous l’égide de la coopération Sud-Sud. L’objectif de cet article est d’exposer, de manière empirique, la complémentarité entre la coopération brésilienne au développement et ses investissements privés dans les secteurs de l’exploitation minière, de l’agriculture et des infrastructures dans le couloir de Nacala dans le nord du Mozambique. L’auteur soutient que des programmes tels que ProSAVANA, conçus pour faciliter les investissements des entreprises en offrant une base technologique et institutionnelle, sont marqués par une approche libérale du développement, approche qui a tendance à renforcer le modèle de croissance extractiviste de l’économie mozambicaine. La société civile du Mozambique et du Brésil s’est opposée à une telle approche et fait pression pour établir une appropriation démocratique d’initiatives de développement.
Bajaj en Égypte ou la diffusion discrète de l’ autorickshaw en Afrique
Authors: Tastevin Yann Philippe
Published: December 2016

Moyen de transport populaire en Inde, le rickshaw à moteur part, au tournant du xxi e siècle, à la conquête du monde. En Égypte, le succès commercial de la technologie indienne montre de manière exemplaire comment à l’axe nord-sud des importations s’ajoutent des flux d’investissement et de technologie entre l’Inde et le continent africain, à l’insu des constructeurs qui dominent la filière automobile. Partant de l’exemple de Bajaj, leader indien aujourd’hui de taille mondiale sur le marché des deux et trois roues, nous proposons d’explorer dans une perspective ethnographique une configuration qui, entre Inde et Égypte, inclut à la fois des individus et des dispositifs industriels. De l’importation à la distribution du véhicule, de l’échange rentable de pièces détachées à sa mécanique, de la filière égyptienne à son extension en Afrique, il s’agira d’analyser les pratiques et la stratégie d’une firme du Sud en voie de multinationalisation.