bluuebunny/crossref_metadata_2025 huggingface dataset:
The inferior medullary velum: anatomical study and neurosurgical relevance
Authors: Tubbs R. Shane , Bosmia Anand N. , Loukas Marios , Hattab Eyas M. , Cohen-Gadol Aaron A.
Published: November 2012

Object

Although it is often visualized surgically, details regarding the inferior medullary velum are lacking in the literature. The present study is intended to better elucidate this neuroanatomical structure using microsurgical and immunohistochemical analyses.

Methods

To study the inferior medullary velum, the authors performed microdissection in 15 adult cadavers. Following gross study, specimens were examined histologically.

Results

The inferior medullary velum extended from the flocculus to the middle cerebellar peduncle and stretched between the inferior cerebellar peduncle and the nodule and pyramid. The average thickness of the velum was found to be 0.5 mm (range 0.35–0.8 mm) and the average length was found to be 6 mm (range 5.5–7.2 mm). Arterial branches were identified in all specimens that arose from medullary branches of the posterior inferior cerebellar artery and supplied the inferior medullary velum. Histologically and from internal to external, a choroid plexus epithelium as a single cell layer was adjacent to a cuboidal layer of ependymal cells with no visible cilia. The next layer contained scattered glia in single cells or small clusters. The most external layer was composed of flat spindle cells resembling fibroblasts. No neurons of any type were identified. Only rare axons traversed the thin hypocellular zone that disappeared toward the midline.

Conclusions

Based on this cadaveric study, the authors conclude that division of the inferior medullary velum should be relatively harmless as no neuronal cells were identified in this structure, which appears to be a vestigial bridge of tissue between the left and right sides of the cerebellum.
Spinal level of myelomeningocele lesion as a contributing factor in posterior fossa volume, intracranial cerebellar volume, and cerebellar ectopia
Authors: Sweeney Kieron J. , Caird John , Sattar Muhammad Taufiq , Allcutt David , Crimmins Darach
Published: November 2012

Object

McLone and Knepper's unified theory of Chiari malformation Type II (CM-II) describes how the loss of CSF via the open posterior neuropore fails to create adequate distending pressure for the developing rhomboencephalic vesicle. The authors of the present article describe the relationship between the posterior fossa volume and intracranial cerebellar volume as being related to the distance from the obex of the fourth ventricle to the myelomeningocele lesion using a common mathematical model, the Hagen-Poiseuille law.

Methods

All newborns who required closure of a myelomeningocele at the authors' institution between 2008 and 2011 and who were between 4 weeks premature and 2 months, corrected gestational age, at the time of MRI were included in this study. Volumes and measurements were obtained from axial and sagittal T2-weighted MR images of the brain and spine.

Results:

A total of 56 newborn infants met the inclusion criteria. There was a direct linear relationship between both posterior fossa volume and cerebellar volume and the spinal level of the myelomeningocele lesion (p = 0.0012 and p = 0.0041, respectively). There was a negative linear relationship between the cerebellar descent, the spinal level of the lesion, and posterior fossa volume and cerebellar volume. These relationships strengthen in patients with no syringomyelia and are not significant in those groups with syringomyelia. The results of a 1-way ANOVA for the 3 groups did not reach significance.

Conclusions

Using a linear equation derived from the Hagen-Poiseuille law that describes pressure in the fourth ventricle as being directly related to the length of the central canal from the obex to the myelomeningocele lesion, the authors were able to explain the directly observed linear relation between posterior fossa volume, intracranial cerebellar volume, and cerebellar descent to the level of the spinal lesion. As this model assumes a uniform radius of the central canal they were able to validate this model when they observed a strengthening in relationships in the no syringomyelia group and statistically insignificant correlations in the groups with syringomyelia. They therefore propose that the spinal level of the lesion is one of the major determinants of posterior fossa volume, intracranial cerebellar volume, and cerebellar ectopia.
Geophysical Survey at Kilwa Kisiwani, Tanzania
Authors: Fleisher Jeffrey , Wynne-Jones Stephanie , Steele Charlene , Welham Kate
Published: November 2012

Geophysical survey at Kilwa Kisiwani, southern Tanzania, has recovered evidence for several aspects of town layout and the use of space within the town that enhance our understandings of this important Swahili site. Although excavations in the 1960s recovered substantial monuments at this stonetown and traced a chronology for the development of the site from the eighth to the sixteenth centuries AD, the overall site layout has remained poorly understood. This paper outlines the possibilities that geophysics creates for positioning the excavations within a broader urban landscape, and reports on a preliminary season of survey at Kilwa. Two areas were the focus of fieldwork during 2011. First the main town centre was surveyed, and the results suggest a denser town plan of coral-built houses that have subsequently been robbed. Second, the enigmatic enclosure of Husuni Ndogo was explored, and revealed evidence for activity relating to metalworking in this monumental space.
Influence de l’environnement sur la gestion des ressources au Néolithique dans la zone refuge du Dhar Néma (Mauritanie sud-orientale)
Authors: Person Alain , Amblard-Pison Sylvie , Jousse Hélène , Vallette Thibault , Albaret Chloé , Raimbault Michel , Maurer Anne-France , Suire Joël
Published: November 2012

Presented here are some aspects of an archaeological investigation conducted in eastern Mauritania in the region of Dhar Nema, a south-eastern extension of the Oualata and Tichitt cliffs (Dhar). This evidence is presented with a focus on its environmental context. The escarpment of the Dhar, a specific geomorphological environment, provided a refuge geoecosystem that continued to supply water during the second part of the Holocene. During the period leading to the current aridity in the southern Sahara, the neolithic populations came there to seek refuge. Amongst more than 70 sites studied, six were chosen that each illustrate a different topographic and ecological context and the interactions of the populations with these. Their location corresponds to varied geological “accidents” oriented perpendicular to the escarpment and in direction of the Baten. In order to survive in this fragile environment during this warming period, the populations developed essential social and technical innovations. These sites have evidenced the characteristics of the evolution of a culture that existed from the 3rd millennium before our era, with notably a social organisation in villages as well as agricultural practices and animal husbandry, which developed from the commencement of their sedentarisation.
Bricoleur and Bricolage: From Metaphor to Universal Concept
Authors: Johnson Christopher
Published: November 2012

Lévi-Strauss's concept of bricolage, first formulated in La Pensée sauvage (The Savage Mind) in 1962, was originally presented as an analogy for how mythical thought works, selecting the fragments or left-overs of previous cultural formations and re-deploying them in new combinations. Significantly, from its source in structural anthropology, the concept has travelled in two directions, towards both the sciences (molecular biology and evolutionary theory) and the humanities (art criticism and critical theory). The aim of this article is to return to Lévi-Strauss's original formulation of bricolage in order to explore the ways in which this technical metaphor transcends its status as simply a metaphor and becomes something like a universal concept. As the key opposition between the bricoleur and the engineer demonstrates, bricolage is also an ideological construct which carries with it a set of suppositions about the nature of science and technology in the post-war world. Looking at the wider scientific imaginary which informs this vision — in particular, Lévi-Strauss's representation of nuclear science — the article concludes by arguing for a more comprehensive understanding of the concept of bricolage as applicable not simply to traditional or residual forms of human activity, but also to the practice — and indeed the essence — of modern scientific and technological development.
‘Genealogical Misfortunes’: Achille Mbembe's (Re-)Writing of Postcolonial Africa
Authors: Syrotinski Michael
Published: November 2012

In his latest work, Sortir de la grande nuit, the Cameroonian social theorist Achille Mbembe nuances his description of the ontological status of the postcolonial African subject, which he had theorized extensively in his best-known text, On the Postcolony, and at the same time exploits the conceptual resources of a number of Jean-Luc Nancy's lexical innovations. This recent text is also a reprise of an earlier autobiographical essay, and the gesture of this ‘reinscription’ is critical to our understanding of Mbembe's status as a contemporary ‘postcolonial thinker’, and the way in which he positions himself in relation to a certain intellectual genealogy of postcolonial theory. Within this trajectory, I argue that we can read fruitfully his relationship to three influential figures: Jacques Derrida, Jean-Luc Nancy and Ruben Um Nyobè.
Methods, Challenges and Potentials of Single Cell RNA-seq
Authors: Hebenstreit Daniel
Published: November 2012

RNA-sequencing (RNA-seq) has become the tool of choice for transcriptomics. Several recent studies demonstrate its successful adaption to single cell analysis. This allows new biological insights into cell differentiation, cell-to-cell variation and gene regulation, and how these aspects depend on each other. Here, I review the current single cell RNA-seq (scRNA-seq) efforts and discuss experimental protocols, challenges and potentials.
Surface Markers for Chondrogenic Determination: A Highlight of Synovium-Derived Stem Cells
Authors: Campbell Douglas , Pei Ming
Published: November 2012

Cartilage tissue engineering is a promising field in regenerative medicine that can provide substantial relief to people suffering from degenerative cartilage disease. Current research shows the greatest chondrogenic potential for healthy articular cartilage growth with minimal hypertrophic differentiation to be from mesenchymal stem cells (MSCs) of synovial origin. These stem cells have the capacity for differentiation into multiple cell lineages related to mesenchymal tissue; however, evidence exists for cell surface markers that specify a greater potential for chondrogenesis than other differentiation fates. This review will examine relevant literature to summarize the chondrogenic differentiation capacities of tested synovium-derived stem cell (SDSC) surface markers, along with a discussion about various other markers that may hold potential, yet require further investigation. With this information, a potential clinical benefit exists to develop a screening system for SDSCs that will produce the healthiest articular cartilage possible.
HIV/AIDS and Associated Conditions among HIV-Infected Refugees in Minnesota, 2000–2007
Authors: Lowther Sara , Johnson Glenise , Hendel-Paterson Brett , Nelson Kailey , Mamo Blain , Krohn Kristina , Pessoa-Brandão Luisa , O'Fallon Ann , Stauffer William
Published: November 2012

In 2010, the requirement for human immunodeficiency virus (HIV) testing of adult refugees prior to US resettlement was removed, thus leading to a potential for missed diagnosis. We reviewed refugee health assessment data and medical charts to evaluate the health status of HIV-infected refugees who arrived in Minnesota during 2000–2007, prior to this 2010 policy change. Among 19,292 resettled adults, 174 were HIV-infected; 169 (97%) were African (median age 26.4 (range: 17–76) years). Charts were abstracted for 157 (124 (79%) with ≥1 year of follow-up). At initial presentation, two of 74 (3%) women were pregnant; 27% became pregnant during follow-up. HIV clinical stage varied (59%, asymptomatic; 11%, mild symptoms; 10%, advanced symptoms; 3%, severe symptoms; 17%, unknown); coinfections were common (51 tuberculosis, 13 hepatitis B, 13 parasites, four syphilis). Prior to arrival 4% had received antiretrovirals. Opportunistic infections were diagnosed among 13%; 2% died from AIDS-related causes. Arrival screening may be needed to identify these HIV-infected refugees and prevent HIV-related morbidity and mortality.
Catalytic Hydrogenation of the Sweet Principles of Stevia rebaudiana, Rebaudioside B, Rebaudioside C, and Rebaudioside D and Sensory Evaluation of Their Reduced Derivatives
Authors: Prakash Indra , Campbell Mary , Chaturvedula Venkata
Published: November 2012

Catalytic hydrogenation of rebaudioside B, rebaudioside C, and rebaudioside D; the three ent-kaurane diterpene glycosides isolated from Stevia rebaudiana was carried out using Pd(OH)2. Reduction of steviol glycosides was performed using straightforward synthetic chemistry with the catalyst Pd(OH)2 and structures of the corresponding dihydro derivatives were characterized on the basis of 1D and 2D nuclear magnetic resonance (NMR) spectral data indicating that all are novel compounds being reported for the first time. Also, the taste properties of all reduced compounds were evaluated against their corresponding original steviol glycosides and sucrose.
The Characterization of SaPIN2b, a Plant Trichome-Localized Proteinase Inhibitor from Solanum americanum
Authors: Luo Ming , Ding Ling-Wen , Ge Zhi-Juan , Wang Zhen-Yu , Hu Bo-Lun , Yang Xiao-Bei , Sun Qiao-Yang , Xu Zeng-Fu
Published: November 2012

Proteinase inhibitors play an important role in plant resistance of insects and pathogens. In this study, we characterized the serine proteinase inhibitor SaPIN2b, which is constitutively expressed in Solanum americanum trichomes and contains two conserved motifs of the proteinase inhibitor II (PIN2) family. The recombinant SaPIN2b (rSaPIN2b), which was expressed in Escherichia coli, was demonstrated to be a potent proteinase inhibitor against a panel of serine proteinases, including subtilisin A, chymotrypsin and trypsin. Moreover, rSaPIN2b also effectively inhibited the proteinase activities of midgut trypsin-like proteinases that were extracted from the devastating pest Helicoverpa armigera. Furthermore, the overexpression of SaPIN2b in transgenic tobacco plants resulted in enhanced resistance against H. armigera. Taken together, our results demonstrated that SaPIN2b is a potent serine proteinase inhibitor that may act as a protective protein in plant defense against insect attacks.
Building Biocompatible Hydrogels for Tissue Engineering of the Brain and Spinal Cord
Authors: Aurand Emily R. , Wagner Jennifer , Lanning Craig , Bjugstad Kimberly B.
Published: November 2012

Tissue engineering strategies employing biomaterials have made great progress in the last few decades. However, the tissues of the brain and spinal cord pose unique challenges due to a separate immune system and their nature as soft tissue. Because of this, neural tissue engineering for the brain and spinal cord may require re-establishing biocompatibility and functionality of biomaterials that have previously been successful for tissue engineering in the body. The goal of this review is to briefly describe the distinctive properties of the central nervous system, specifically the neuroimmune response, and to describe the factors which contribute to building polymer hydrogels compatible with this tissue. These factors include polymer chemistry, polymerization and degradation, and the physical and mechanical properties of the hydrogel. By understanding the necessities in making hydrogels biocompatible with tissue of the brain and spinal cord, tissue engineers can then functionalize these materials for repairing and replacing tissue in the central nervous system.
Microscopic Analysis of Current and Mechanical Properties of Nafion® Studied by Atomic Force Microscopy
Authors: Hiesgen Renate , Helmly Stefan , Galm Ines , Morawietz Tobias , Handl Michael , Friedrich K.
Published: November 2012

The conductivity of fuel cell membranes as well as their mechanical properties at the nanometer scale were characterized using advanced tapping mode atomic force microscopy (AFM) techniques. AFM produces high-resolution images under continuous current flow of the conductive structure at the membrane surface and provides some insight into the bulk conducting network in Nafion membranes. The correlation of conductivity with other mechanical properties, such as adhesion force, deformation and stiffness, were simultaneously measured with the current and provided an indication of subsurface phase separations and phase distribution at the surface of the membrane. The distribution of conductive pores at the surface was identified by the formation of water droplets. A comparison of nanostructure models with high-resolution current images is discussed in detail.
Amelioration of Dextran Sodium Sulfate-Induced Colitis in Mice by Rhodobacter sphaeroides Extract
Authors: Liu Wen-Sheng , Chen Man-Chin , Chiu Kuo-Hsun , Wen Zhi-Hong , Lee Che-Hsin
Published: November 2012

Bacteria can produce some compounds in response to their environment. These compounds are widely used in cosmetic and pharmaceutical applications. Some probiotics have immunomodulatory activities and modulate the symptoms of several diseases. Autoimmune diseases represent a complex group of conditions that are thought to be mediated through the development of autoreactive immunoresponses. Inflammatory bowel disease (IBD) is common autoimmune disease that affects many individuals worldwide. Previously, we found that the extracts of Rhodobacter sphaeroides (Lycogen) inhibited nitric oxide production and inducible nitric-oxide synthase expression in activated macrophages. In this study, the effect of Lycogen™, a potent anti-inflammatory agent, was evaluated in mice with dextran sodium sulfate (DSS)-induced colitis. Oral administration of Lycogen™ reduced the expressions of proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) in female BABL/c mice. In addition, the increased number of bacterial flora in the colon induced by DSS was amelirated by Lycogen™. The histological score of intestinal inflammation in 5% DSS-treated mice after oral administration of Lycogen™ was lower than that of control mice. Meanwhile, Lycogen™ dramatically prolonged the survival of mice with severe colitis. These findings identified that Lycogen™ is an anti-inflammatory agent with the capacity to ameliorate DSS-induced colitis.
Monoterpenoid Indole Alkaloids from Alstonia yunnanensis and Their Cytotoxic and Anti-inflammatory Activities
Authors: Cao Peng , Liang Yong , Gao Xu , Li Xiao-Ming , Song Zhen-Quan , Liang Guobiao
Published: November 2012

The 80% ethanol extract of Alstonia yunnanensis afforded five new monoterpenoid indole alkaloids: 11-hydroxy-6,7-epoxy-8-oxo-vincadifformine (1), 14-chloro-15-hydroxy- vincadifformine (2), perakine N4-oxide (3), raucaffrinoline N4-oxide (4), and vinorine N1,N4-dioxide (5), together with three known compounds: 11-methoxy-6,7-epoxy-8-oxo- vincadifformine (6), vinorine N4-oxide (7) and vinorine (8). The structures of the isolated compounds were established based on 1D and 2D (1H-1H-COSY, HMQC, HMBC, and ROESY) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated compounds were tested in vitro for cytotoxic potential against seven tumor cell lines and anti-inflammatory activities. Compounds 3, 4 and 7 exhibited weak cytotoxicity against the tested cell lines and selective inhibition of Cox-2 (>85%).
Analysis of Cross-Seasonal Spectral Response from Kettle Holes: Application of Remote Sensing Techniques for Chlorophyll Estimation
Authors: Igamberdiev Rahmatulla , Bill Ralf , Schubert Hendrik , Lennartz Bernd
Published: November 2012

Kettle holes, small inland water bodies usually less than 1 ha in size, are subjected to pollution, drainage, and structural alteration by intensive land use practices. This study presents the analysis of spectral signatures from kettle holes based on in situ water sampling and reflectance measurements in application for chlorophyll estimation. Water samples and surface reflectance from kettle holes were collected from 6 ponds in 15 field campaigns (5 in 2007 and 10 in 2008), resulting in a total of 80 spectral datasets. We assessed the existing semi-empirical algorithms to determine chlorophyll content for different types of kettle holes using seasonal and cross-seasonal volume reflectance and derivative spectra. Based on this analysis and optical properties of water leaving reflectance from kettle holes, the following typology of the remote signal interpretation was proposed: Submerged vegetation, Phytoplankton dominated and Mixed type.
Enzymatic Modification of Polyethersulfone Membranes
Authors: Nady Norhan , Franssen Maurice , Zuilhof Han , Boom Remko , Schroën Karin
Published: November 2012

Enzymatic modification of polyethersulfone (PES) membranes has been found not only feasible, but also an environmentally attractive way to vary surface properties systematically. In this paper, we summarize the effect of modification layers on protein adsorption and bacterial adhesion on PES membranes and surfaces. The enzyme laccase was used to covalently bind (poly)phenolic acids to the membrane, and compared to other membrane modification methods, this method is very mild and did not influence the mechanical strength negatively. Depending on the conditions used during modification, the modification layers were capable of influencing interactions with typical fouling species, such as protein, and to influence attachment of microorganisms. We also show that the modification method can be successfully applied to hollow fiber membranes; and depending on the pore size of the base membrane, proteins were partially rejected by the membrane. In conclusion, we have shown that enzymatic membrane modification is a versatile and economically attractive method that can be used to influence various interactions that normally lead to surface contamination, pore blocking, and considerable flux loss in membranes.
Arthroscopic treatment of fragmented coronoid process with severe elbow incongruity
Authors: de Bakker E. , Van Vynckt D. , Coppieters E. , van Bree H. , Van Ryssen B. , Samoy Y. C. A.
Published: November 2012

The purpose of this study was to investigate the long-term treatment results of fragmented coronoid process (FCP) in joints with a radio-ulnar step greater than 3 mm. Treatment of these patients only consisted of fragment removal, without correction of the incongruity.

The eight Bernese Mountain Dogs (11 joints) included in this study showed obvious clinical signs of elbow disease and were diagnosed with severe elbow incongruity and concomitant FCP in the time period from 1999–2003. At that time, elbow radiography, computed tomography, and arthroscopy were performed. The mean follow-up period was 5.6 years. The follow-up consisted of a telephone questionnaire combined with a clinical and radiographic re-evaluation at our clinic.

The questionnaire revealed that all dogs were either free of lameness or only lame following heavy exercise. One dog sporadically required medication after heavy exercise. The owner satisfaction rate was 100%. The clinical re-evaluation did not reveal any signs of pain or lameness in all cases. Range-of- motion was decreased in nine of the 11 elbows. Radiographs revealed an increase in severity of osteoarthritis in every case.

In this case series, arthroscopic fragment removal without treatment of incongruity was demonstrated to be a valuable treatment option and may provide a satisfactory long-term outcome.
Detection of meniscal tears by arthroscopy and arthrotomy in dogs with cranial cruciate ligament rupture
Authors: Plesman R. , Campbell J. , Gilbert P.
Published: November 2012

Objectives: To evaluate and compare detection of meniscal tears associated with cranial cruciate ligament insufficiency by either arthroscopy or arthrotomy.

Methods: A retrospective, cohort study was completed with stifles (n = 531) of dogs with cranial cruciate ligament rupture. Either a medial parapatellar arthrotomy or an arthroscopy procedure was performed and groups were compared for significant differences in meniscal tears detected using logistic regression analysis.

Results: Arthroscopy was performed on 58.8% and arthrotomy on 41.2% of the stifles. In total, 44.4% of the examined stifles had meniscal tears. Meniscal tears were found in 38.8% of the stifles examined by arthrotomy, and 48.4% of those examined by arthroscopy. Overall, the rate of detection of a meniscal tear was significantly different (p = 0.019) between the groups, and meniscal tears were observed more frequently by arthroscopy than by arthrotomy (odds ratio 1.54; 95% confidence interval 1.07 – 2.22).

Clinical significance: These results suggest that arthroscopy may be more sensitive than arthrotomy for detection of meniscal pathology in clinical patients. However, these results must be interpreted with caution since this was a retrospective study. Randomized prospective clinical studies are required to further test this hypothesis.
Myositis ossificans circumscripta of the triceps muscle in a Rottweiler dog
Authors: Palumbo Piccionello A. , Dini F. , Vullo C. , Rossi G. , Scrollavezza P. , Tambella A. M.
Published: November 2012

A 20-month-old male Rottweiler dog was presented with the complaint of chronic right forelimb lameness that was unresponsive to conservative treatment. Physical examination allowed for the topographical identification of the source of the problem as a firm enlargement of the soft tissues that was partially movable from humeral bone and compatible with an alteration of the triceps brachii muscle. Radiographic images showed signs that were highly suggestive of myositis ossificans. Computed tomography allowed for a more accurate characterization of the lesion, to exclude involvement of the elbow joint and humeral bone, and to localize anatomically the lesion in the caput accessorium and longum of the triceps brachii muscle. Surgical excision of the ossified portion of the triceps muscle was performed. Histological examination of the excised tissue substantiated the diagnosis of myositis ossificans. A one year clinical and radiographic follow-up examination showed a complete recovery, with no evidence of complications or recurrence. Despite myositis ossificans in dogs having previously been identified in the hindlimbs, this case of myositis ossificans circumscripta of the triceps muscle suggests that it may also occur in the muscles of the forelimb.
Tricyclic flavonoids with 1,3-dithiolium substructure
Authors: Bahrin Lucian G , Jones Peter G , Hopf Henning
Published: November 2012

The synthesis of new 3-dithiocarbamic flavonoids has been accomplished by the reaction of the corresponding 2-hydroxyaryl dithiocarbamates with aminals. These flavonoids were obtained as a mixture of diastereoisomers, the anti isomer being the major one. The heterocyclization of these compounds provided novel tricyclic flavonoids bearing a 1,3-dithiolium-2-yl ring fused at the 3,4-carbon positions of the benzopyran moiety.
Charting the Evolution of Structure and Determinacy in State Sentencing and Corrections Policies 1970–2010
Authors: Stemen Don , Rengifo Andres F.
Published: November 2012

This study examines state policies governing criminal sentencing and prison release decisions between 1970 and 2010. The goal is to create common definitions and operationalizations of policies to better specify state-level policy differences over time and across jurisdictions. Relying on an independent review of state codes, we define and catalogue key legislative initiatives adopted across the states, including presumptive sentences, sentencing guidelines, and the abolition of discretionary release. We argue that a set of common definitions and accounting is necessary for enhancing research on the content, adoption, and impact of policies and for assisting policymakers in the development of reform initiatives in the areas of sentencing and corrections.
Understanding Police Gang Data at the Aggregate Level: An Examination of the Reliability of National Youth Gang Survey Data (Research Note)
Authors: Katz Charles M. , Fox Andrew M. , Britt Chester L. , Stevenson Phillip
Published: November 2012

The National Youth Gang Survey (NYGS) is an annual survey of a nationally representative sample of police agencies administered by the National Gang Center that provides data on the number of gangs, gang members, and gang homicides across jurisdictions. The focus of the current study is the reliability of key measures of gang behavior measured by the NYGS. Specifically, the current study assesses NYGS data from 2005 to 2009 in terms of missing data, test-retest reliability, internal consistency reliability, and inter-observer reliability. Results showed low levels of missing data for number of gangs and number of gang homicides in jurisdictions with fewer than 200,000 people, while measures of number of gang members and gang homicides in jurisdictions over 200,000 people had missing data from about 30% of participating jurisdictions. The findings also suggest that the NYGS data on gangs and gang members are generally highly reliable. Data on gang homicides also exhibited a high degree of reliability, but only for jurisdictions with populations over 200,000. Implications of the findings and recommendations for future research are discussed.
Drug Treatment Courts: A Quantitative Review of Study and Treatment Quality
Authors: Gutierrez Leticia , Bourgon Guy
Published: November 2012

The effectiveness of drug courts has been the subject of numerous studies, and three major meta-analyses have examined many of these studies in regard to two main factors: (1) study quality and (2) treatment quality. The current study examines these two factors more closely. Study quality was assessed using the Collaborative Outcome Data Committee Guidelines (CODC); studies were rated as “rejected,” “weak,” “good,” or “strong” based on methodological quality. Drug court treatment quality was assessed by evaluating adherence to the principles of Risk-Need-Responsivity (RNR). The RNR principles have been previously shown to mediate the effectiveness of offender treatment across various offender groups and a variety of criminogenic needs. In total, 96 studies were reviewed and assessed according to study and treatment quality. Results found that the study quality of the literature is poor and that this accounts for much of the variability in findings seen across studies. Furthermore, analyses revealed that although adherence to the RNR principles was poor, increasing adherence to RNR resulted in more effective treatment of offenders and reduced recidivism. Using only methodologically acceptable studies, the least biased estimate of the effectiveness of drug courts in reducing recidivism was found to be approximately 8%.
Examining Metal Theft in Context: An Opportunity Theory Approach
Authors: Posick Chad , Rocque Michael , Whiteacre Kevin , Mazeika David
Published: November 2012

Although law enforcement agencies, policymakers, and communities have had to confront the issue of increasing metal theft for the past several years, almost no academic literature has attempted to examine the correlates of metal theft and subsequent policy implications. This exploratory study profiles the theft of metal from commercial and residential dwellings through analysis of recorded crime data from April 2008 through July 2010 in Rochester, New York. An opportunity framework guided the analyses. Spatial, trend, and multivariate logistic regression analyses were used to examine and better understand metal theft. Results indicate that an opportunity theory approach is useful in addressing metal theft and that this framework provides explicit implications for local law enforcement and policymakers.
Learning in Games : Neural Computations underlying Strategic Learning
Authors: Hsu Ming , Zhu Lusha
Published: November 2012

Résumé Les dernières décennies ont connu une croissance inédite de notre compréhension des fondements cérébraux de la prise de décision économique. En particulier, la recherche a découvert non seulement la localisation de régions du cerveau où certains processus ont lieu, mais également la nature de variables latentes (économiquement significatives) ainsi que la manière dont elles sont liées au comportement. Cette transition d’une compréhension du lieu de la décision économique vers la manière dont se prend cette décision au niveau cérébral est intégrante à l’identification d’une relation entre processus nerveux et modèles de comportements économiques. Toutefois, le progrès accompli a été inégal. Les études neuro-économiques sur la prise de décision individuelle, telles que celles impliquant les préférences temporelles ou l’attitude face au risque, ont l’avantage de s’inscrire dans des décennies d’études neuroscientifiques sur les comportements animaliers. La plupart de ces résultats sont basés sur des approches quantitatives et informatiques, qui se prêtent aisément à l’expérimentation économique. En revanche, notre compréhension des systèmes nerveux sous-jacents au comportement social est bien moins spécifique. Une grande partie du défi actuel résulte des lacunes empiriques des prédictions de comportement issues de la théorie des jeux standard, qui sont largement basées sur l’équilibre. Utilisant notre propre étude comme exemple, nous montrons comment il est possible de chercher directement les variables latentes induites par les modèles actuels d’apprentissage stratégique, et de tenter de les localiser dans le cerveau. Plus précisément, nous montrons que les systèmes nerveux sous-jacents à l’apprentissage stratégique s’ajoutent à ceux impliqués dans l’apprentissage par essais-erreurs, mais incluent également des calculs additionnels qui captent l’apprentissage basé sur la croyance. Finalement, nous discutons la manière dont notre approche peut être élargie pour traiter les problèmes fondamentaux de l’économie. Classification JEL : C92, D83.
Un nuevo modelo fenomenológico y diferencial para predecir la respuesta mecánica de materiales metálicos policristalinos sometidos a deformación en caliente
Authors: Castellanos J. , Muñoz J. , Gutiérrez V. , Rieiro I. , Ruano O. A. , Carsí M.
Published: November 2012

Este trabajo presenta un nuevo modelo fenomenológico y diferencial (que emplea ecuaciones diferenciales) para predecir la respuesta mecánica de un material metálico policristalino sometido a deformación en caliente. El modelo, llamado MCC, depende de seis parámetros y utiliza dos variables internas para considerar los procesos de endurecimiento por deformación, restauración y recristalización dinámicas. La validación experimental del modelo MCC se ha realizado empleando curvas tensión-deformación procedentes de ensayos de torsión a alta temperatura (900 ºC a 1.200 ºC) y moderadamente alta velocidad de deformación (0,005 s-1 a 5 s-1) sobre un acero de alto contenido en nitrógeno. Los resultados obtenidos revelan la concordancia significativa entre las tensiones experimentales y predichas. Además el parámetro a de Garofalo y la deformación para el 50 % de volumen recristalizado se han utilizado como elementos de control para realizar un primer paso en la interpretación física de las variables y parámetros del modelo MCC.
Emission and transport of bromocarbons: from the West Pacific ocean into the stratosphere
Authors: Tegtmeier S. , Krüger K. , Quack B. , Atlas E. L. , Pisso I. , Stohl A. , Yang X.
Published: November 2012

Abstract. Oceanic emissions of halogenated very short-lived substances (VSLS) are expected to contribute significantly to the stratospheric halogen loading and therefore to ozone depletion. The amount of VSLS transported into the stratosphere is estimated based on in-situ observations around the tropical tropopause layer (TTL) and on modeling studies which mostly use prescribed global emission scenarios to reproduce observed atmospheric concentrations. In addition to upper-air VSLS measurements, direct observations of oceanic VSLS emissions are available along ship cruise tracks. Here we use such in-situ observations of VSLS emissions from the West Pacific and tropical Atlantic together with an atmospheric Lagrangian transport model to estimate the direct contribution of bromoform (CHBr3), and dibromomethane (CH2Br2) to the stratospheric bromine loading as well as their ozone depletion potential. Our emission-based estimates of VSLS profiles are compared to upper-air observations and thus link observed oceanic emissions and in situ TTL measurements. This comparison determines how VSLS emissions and transport in the cruise track regions contribute to global upper-air VSLS estimates. The West Pacific emission-based profiles and the global upper-air observations of CHBr3 show a relatively good agreement indicating that emissions from the West Pacific provide an average contribution to the global CHBr3 budget. The tropical Atlantic, although also being a CHBr3 source region, is of less importance for global upper-air CHBr3 estimates as revealed by the small emission-based abundances in the TTL. Western Pacific CH2Br2 emission-based estimates are considerably smaller than upper-air observations as a result of the relatively low sea-to-air flux found in the West Pacific. Together, CHBr3 and CH2Br2 emissions from the West Pacific are projected to contribute to the stratospheric bromine budget with 0.4 pptv Br on average and 2.3 pptv Br for cases of maximum emissions through product and source gas injection. These relatively low estimates reveal that the tropical West Pacific, although characterized by strong convective transport, might overall contribute less VSLS to the stratospheric bromine budget than other regions as a result of only low CH2Br2 and moderate CHBr3 oceanic emissions.
Effects of atmospheric conditions on ice nucleation activity of Pseudomonas
Authors: Attard E. , Yang H. , Delort A.-M. , Amato P. , Pöschl U. , Glaux C. , Koop T. , Morris C. E.
Published: November 2012

Abstract. Although ice nuclei from bacterial origin are known to be efficient at the highest temperatures known for ice catalysts, quantitative data are still needed to assess their role in cloud processes. Here we studied the effects of three typical cloud conditions (i) acidic pH (ii) NO2 and O3 exposure and (iii) UV-A exposure on the ice nucleation activity (INA) of four Pseudomonas strains. Three of the Pseudomonas syringae strains were isolated from cloud water and the phyllosphere and Pseudomonas fluorescens strain CGina-01 was isolated from Antarctic glacier ice melt. Among the three conditions tested, acidic pH caused the most significant effects on INA likely due to denaturation of the ice nucleation protein complex. Exposure to NO2 and O3 gases had no significant or only weak effects on the INA of two P. syringae strains whereas the INA of P. fluorescens CGina-01 was significantly affected. The INA of the third P. syringae strain showed variable responses to NO2 and O3 exposure. These differences in the INA of different Pseudomonas suggest that the response to atmospheric conditions could be strain-specific. After UV-A exposure, a substantial loss of viability of all four strains was observed whereas their INA decreased only slightly. This corroborates the notion that under certain conditions dead bacterial cells can maintain their INA. Overall, the negative effects of the three environmental factors on INA were more significant at the warmer temperatures. Our results suggest that in clouds where temperatures are near 0 °C, the importance of bacterial ice nucleation in precipitation processes could be reduced by some environmental factors.
Artificial primary marine aerosol production: a laboratory study with varying water temperature, salinity, and succinic acid concentration
Authors: Zábori J. , Matisāns M. , Krejci R. , Nilsson E. D. , Ström J.
Published: November 2012

Abstract. Primary marine aerosols are an important component of the climate system, especially in the remote marine environment. With diminishing sea-ice cover, better understanding of the role of sea spray aerosol on climate in the polar regions is required. As for Arctic Ocean water, laboratory experiments with NaCl water confirm that a few degrees change in the water temperature (Tw) gives a large change in the number of primary particles. Small particles with a dry diameter between 0.01 μm and 0.25 μm dominate the aerosol number density, but their relative dominance decreases with increasing water temperature from 0 °C where they represent 85–90% of the total aerosol number to 10 °C, where they represent 60–70% of the total aerosol number. This effect is most likely related to a change in physical properties and not to modification of sea water chemistry. A change of salinity between 15 g kg−1 and 35 g kg−1 did not influence the shape of a particle number size distribution. Although the magnitude of the size distribution for a water temperature change between 0 °C and 16 °C changed, the shape did not. An experiment where succinic acid was added to a NaCl water solution showed, that the number concentration of particles with 0.010 μm < Dp < 4.5 μm decreased on average by 10% when the succinic acid concentration in NaCl water at a water temperature of 0 °C was increased from 0 μmol L−1 to 94 μmol L−1. A shift to larger sizes in the particle number size distribution is observed from pure NaCl water to Arctic Ocean water. This is likely a consequence of organics and different inorganic salts present in Arctic Ocean water in addition to the NaCl.
Long-term volatility measurements of submicron atmospheric aerosol in Hyytiälä, Finland
Authors: Häkkinen S. A. K. , Äijälä M. , Lehtipalo K. , Junninen H. , Backman J. , Virkkula A. , Nieminen T. , Vestenius M. , Hakola H. , Ehn M. , Worsnop D. R. , Kulmala M. , Petäjä T. , Riipinen I.
Published: November 2012

Abstract. The volatility of submicron atmospheric aerosol particles was investigated at a boreal forest site in Hyytiälä, Finland from January 2008 to May 2010. These long-term observations allowed for studying the seasonal behavior of aerosol evaporation with a special focus on compounds that remained in the aerosol phase at 280 °C. The temperature-response of evaporation was also studied by heating the aerosol sample step-wise to six temperatures ranging from 80 °C to 280 °C. The mass fraction remaining after heating (MFR) was determined from the measured particle number size distributions before and after heating assuming a constant particle density (1.6 g cm−3). On average 19% of the total aerosol mass remained in the particulate phase at 280 °C. The particles evaporated less at low ambient temperatures during winter as compared with the warmer months. Black carbon (BC) fraction of aerosol mass correlated positively with the MFR at 280 °C, but could not explain it completely: most of the time a notable fraction of this non-volatile residual was something other than BC. Using additional information on ambient meteorological conditions and results from an Aerodyne aerosol mass spectrometer (AMS), the chemical composition of MFR at 280 °C and its seasonal behavior was further examined. Correlation analysis with ambient temperature and mass fractions of polycyclic aromatic hydrocarbons (PAHs) indicated that MFR at 280 °C is probably affected by anthropogenic emissions. On the other hand, results from the AMS analysis suggested that there may be very low-volatile organics, possibly organonitrates, in the non-volatile (at 280 °C) fraction of aerosol mass.
Functionalization and fragmentation during ambient organic aerosol aging: application of the 2-D volatility basis set to field studies
Authors: Murphy B. N. , Donahue N. M. , Fountoukis C. , Dall'Osto M. , O'Dowd C. , Kiendler-Scharr A. , Pandis S. N.
Published: November 2012

Abstract. Multigenerational oxidation chemistry of atmospheric organic compounds and its effects on aerosol loadings and chemical composition is investigated by implementing the Two-Dimensional Volatility Basis Set (2-D-VBS) in a Lagrangian host chemical transport model. Three model formulations were chosen to explore the complex interactions between functionalization and fragmentation processes during gas-phase oxidation of organic compounds by the hydroxyl radical. The base case model employs a conservative transformation by assuming a reduction of one order of magnitude in effective saturation concentration and an increase of oxygen content by one or two oxygen atoms per oxidation generation. A second scheme simulates functionalization in more detail using group contribution theory to estimate the effects of oxygen addition to the carbon backbone on the compound volatility. Finally, a fragmentation scheme is added to the detailed functionalization scheme to create a functionalization-fragmentation parameterization. Two condensed-phase chemistry pathways are also implemented as additional sensitivity tests to simulate (1) heterogeneous oxidation via OH uptake to the particle-phase and (2) aqueous-phase chemistry of glyoxal and methylglyoxal. The model is applied to summer and winter periods at three sites where observations of organic aerosol (OA) mass and O:C were obtained during the European Integrated Project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) campaigns. The base case model reproduces observed mass concentrations and O:C well, with fractional errors (FE) lower than 55% and 25%, respectively. The detailed functionalization scheme tends to overpredict OA concentrations, especially in the summertime, and also underpredicts O:C by approximately a factor of 2. The detailed functionalization model with fragmentation agrees well with the observations for OA concentration, but still underpredicts O:C. Both heterogeneous oxidation and aqueous-phase processing have small effects on OA levels but heterogeneous oxidation, as implemented here, does enhance O:C by about 0.1. The different schemes result in very different fractional attribution for OA between anthropogenic and biogenic sources.