bluuebunny/crossref_metadata_2025 huggingface dataset:
The Design and Implementation of Customary Land Reforms in Central Malawi
Authors: Ng'ong'ola Clement
Published: July 2009

In 1967 the Malawi Parliament passed a set of statutes which were intended to provide a new legal framework for rural agrarian change. The President, Dr. Banda, emphasised during the proceedings that existing customs for holding and tilling land were outdated, wasteful and totally unsuitable for the development of a country with agriculture as the basis of the economy. He suggested that the main problem was the absence of individual titles:

“No one is responsible & for the uneconomic and wasted use of land because no one holds land as an individual. Land is held in common & and everybody's baby is nobody's baby at all.”

He argued that the existing laws and customs discouraged individuals and institutions from providing loans for the development of land. New laws were therefore required to ameliorate the situation:

These remarks were not completely novel; they echoed and repeated recommendations in the reports of the East Africa Royal Commission, 1953–55, and the Conference on African Land Tenure in East and Central Africa held in Arusha, Tanzania, in 1956. The defects of customary land tenure pertaining to shifting cultivation and the preponderance of group control over land holding and use which the Malawi President particularized were not the only justifications for reform. The reports suggested that tenure reforms were necessary where population explosion and shortage of land contributed to the uncontrolled emergence of land dealings; where unfixed and uncertain customary land boundaries contributed to excessive land litigation; and where succession rules led to excessive fragmentation and sub-division of holdings.
The Organization of African Unity and the Saharan Arab Democratic Republic
Authors: Naldi J.
Published: July 2009

The long-standing Western Sahara dispute which has plagued the OAU finally came to a head in August, 1982, when, as a consequence of the admission of the Saharan Arab Democratic Republic to the Organization earlier in the year, the Nineteenth Summit Conference due to have been held in Tripoli was postponedsine die. Following a Moroccan-inspired boycott, an insufficient quorum existed to allow the meeting to proceed. The Western Sahara dispute has emphasised some of the shortcomings of the OAU. Although it may have been initially assumed that the OAU was better suited to handle this dispute, it was handicapped by the intransigent attitudes of the parties to the dispute. Threats to cancel membership of the Organization if the SADR was ever admitted were repeatedly made by Morocco and some of her allies. The SADR secured membership of the OAU in February, 1982, and the worst fears appear to have been confirmed. The question therefore arises as to what the future holds for the OAU, but first it is necessary to examine how the SADR was admitted to the OAU.
Ten Years of the Botswana Matrimonial Causes Act—Further Proposals for Divorce Reform
Authors: Sanders A. J. G. M.
Published: July 2009

The Matrimonial Causes Act, 1 of 1973 (Cap. 29:07 of the Laws of Botswana) was passed by the National Assembly on 27 October, 1972. It was assented to by the then President of Botswana, the late Sir Seretse Khama, on 2 February, 1973, and entered into force a week later on 9 February, 1973. The Act applies to civil marriages only, i.e. marriages concluded in terms of the Marriage Act (Cap. 29:01); customary law marriages have been excluded from its operation. As its short title indicates, the Act deals with matrimonial causes, that is to say divorce, judicial separation and the annulment of marriages and matters incidental thereto such as the property rights of spouses, custody, guardianship, maintenance and the jurisdiction of the courts.

During its first 10 years of existence the Act has been the subject-matter of many a decision of the High Court and provisions of it have been considered also by the Court of Appeal. Most of these decisions deal with divorce. In academic circles, too, the Act received attention, witness the review by Chris Himsworth in theJournal of African Law. This review was written immediately after the Act came into force. An updated account is therefore appropriate. As I intend to approach the Act from a broader historical and jurisprudential angle, I will deal with it afresh rather than use Himsworth's penetrating but positivistic analysis as a frame of reference.
The Lagos Plan of Action—Legal Mechanisms for Co-Operation Between the Organisation of African Unity and the United Nations Economic Commission for Africa
Authors: D'Sa Rose M.
Published: July 2009

The African continent represents a region which faces economic problems of the utmost severity at a time when the global economy itself is ravaged by inflation, unemployment and the effects of a world recession. Africa contains 21 of the world's 45 least-developed nations. Its total Gross National Product accounts for only 2·7 per cent. of the world's Product and Africa has the lowest average per capita income in the world. Many African countries lack basic medical and health care facilities while food shortages and severe unemployment affect a very high proportion of African peoples. Internal African development strategies of the past have been subjected to critical investigation in an attempt to assess the sources of the continent's development problems. Despite its vast natural resources and the praiseworthy efforts of many African governments, the continent as a whole (excluding South Africa) is unable to show any significant economic expansion or growth.

The 1980 Lagos Plan of Action represents the most recent initiative undertaken by the Organisation of African Unity (O.A.U.) in conjunction with the U.N. Economic Commission for Africa (E.C.A.) to develop a successful regional strategy for African development. It aims at economic growth in each individual African state in different sectors including food and agriculture, industry and in environmental and energy matters. It adopts specific as well as general targets with time limits, for each aspect of economic planning.
Parasites ofApollonia melanostoma(Pallas 1814) andNeogobius kessleri(Guenther 1861) (Osteichthyes, Gobiidae) from the Danube River in Austria
Authors: Mühlegger J.M. , Jirsa F. , Konecny R. , Frank C.
Published: July 2009

Two invasive fish species, the round gobyApollonia melanostomasyn.Neogobius melanostomus(Pallas 1814) and the bighead gobyNeogobius kessleri(Günther, 1861), have established a firm population in Austrian waters during the past 15 years. As there have been no records of the parasite fauna from these populations, a total of 79 specimens ofA. melanostomaand 12 specimens ofN. kessleriwere examined for parasites between May and October 2007 from three different sampling sites from the Danube River in Austria. In total 12 parasite taxa were recovered. The protozoansTrichodinasp. andIchthyophthirius multifiliisfrom the gills and skin; two crustacean species,Paraergasilus brevidigitusandErgasilus sieboldi, from the gills; and the two monogeneansGyrodactylussp. andDactylogyrussp., from the skin and gills respectively, all occurred at low prevalence and intensities. Furthermore, cystacanths of the acanthocephalanAcanthocephalus luciiwere found in the body cavity. Metacercariae of the digeneansDiplostomumsp. andTylodelphys clavatawere found in the lens of the eye and the vitreous humour, respectively. Adults of two digeneans,Nicolla skrjabiniandBunodera nodulosa, were found in the intestine. In addition, during this survey metacercariae of the Holarctic digeneanBucephalus polymorphus, encysted in the skin and fins, with prevalence up to 78%, were recorded for the first time in Austria.
Gastro-intestinal nematode infections in goats relative to season, host sex and age from the Kashmir valley, India
Authors: Tariq K.A. , Chishti M.Z. , Ahmad F.
Published: July 2009

The present study aimed to investigate the seasonal epidemiological prevalence of gastro-intestinal nematodes (GINs) of goats with respect to sex and age of the host in the Kashmir valley from 1 February 2005 to 31 January 2007. A total of 1267 goats were examined [faecal examination: 938 (year 1: 470; year 2: 468); gastro-intestinal (GIT) examination: 329 (year 1: 175; year 2: 154)]. The overall prevalence of GIN infection in these animals was 54.3% (year 1: 54.8%; year 2: 53.8%; P = 0.842). The different parasites reported with their respective prevalences (%) were: Haemonchus contortus (48.3); Bunostomum trigonocephalum (30.1); Chabertia. ovina (29.8); Ostertagia circumcincta (29.8); Nematodirus spathiger (25.2); Trichostrongylus spp. (25.1); Oesophagostomum columbianum (23.5); Trichuris ovis (19.0); and Marshallagia marshalli (16.6). The mean maximum prevalence of GIN infection (faecal examination: 75.6 ± 0.20; GIT examination: 85.3 ± 0.95), faecal egg counts (2552 ± 85.7) and average worm burden (333.25 ± 2.25) were found in the summer and they were lowest in winter (prevalence: faecal examination, 23.2 ± 0.95; GIT examination, 12.7 ± 0.20; faecal egg counts: 134.15 ± 9.15; and average worm burden: 79.8 ± 52.2), with significant differences between the seasons (P < 0.05). The sex of the hosts was not an important factor influencing the prevalence of GIN infection. With the increase in host age, prevalence of infection decreased significantly (P ≥ 0.05). Thus seasonal dynamics and age of the host animals significantly influenced the prevalence of GIN infection. The above findings will be helpful in devising the appropriate control strategies for GINs of goats reared under the traditional husbandry system in temperate agro-climatic conditions in the Kashmir valley as well as in similar climatic zones of other parts of the world.
Landau damped kinetic Alfvén waves and coronal heating
Authors: SHARMA R. P. , KUMAR SACHIN
Published: July 2009

Some recent observations of solar corona suggest that the kinetic Alfvén waves (KAWs) turbulence may be responsible for electron acceleration in solar corona and coronal heating. In the present research, we investigate the turbulent spectra of KAW due to filamentation process in the presence of Landau damping and particle energization. We present here the numerical simulation of model equation governing the nonlinear dynamics of the KAW in the presence of Landau damping. When the ponderomotive and Joule heating nonlinearities are incorporated in the KAW dynamics, the power spectra of the turbulent field is evaluated and used for particle heating. Our results reveal the formation of damped coherent magnetic filamentary structures and the turbulent spectra. The effect of Landau damping is to make the turbulent spectra steeper. Two types of scalings k−3.6 and k−4 have been obtained. We have studied the turbulence with different initial conditions. Using the Fokker–Planck equation with the new velocity space diffusion coefficient, we find the distribution function of energetic electrons in these turbulent structures. Landau damped KAWs may be responsible for the acceleration of the energetic electrons in solar corona and coronal heating.
Molecular epidemiology ofSchistosoma mansoniin Uganda: DNA barcoding reveals substantial genetic diversity within Lake Albert and Lake Victoria populations
Authors: STOTHARD J. R. , WEBSTER B. L. , WEBER T. , NYAKAANA S. , WEBSTER J. P. , KAZIBWE F. , KABATEREINE N. B. , ROLLINSON D.
Published: July 2009

Representative samples of UgandanSchistosoma mansonifrom Lake Albert and Lake Victoria were examined using DNA barcoding, sequence analysis of two partially overlapping regions – ASMIT (396 bp) & MORGAN (617 bp) – of the mitochondrial cytochrome oxidase subunit I (cox1). The Victorian sample exhibited greater nucleotide diversity, 1·4%vs. 1·0%, and a significant population partition appeared as barcodes did not cross-over between lakes. With one exception, Lake Albert populations were more mixed by sampled location, while those from Lake Victoria appeared more secluded. Using statistical parsimony, barcode ASMIT 1 was putatively ancestral to all others and analysis of MORGAN cox1 confirmed population diversity. All samples fell into two of five well-resolved lineages; sub-lineages therein broadly partitioning by lake. It seems that barcode ASMIT 1 (and close variants) was likely widely dispersed throughout the Nilotic environment but later diversifiedin situ, and in parallel, within Lake Albert and Lake Victoria. The genetic uniformity of UgandanS. mansonican no longer be assumed, which might better explain known epidemiological heterogeneities. While it appears plausible that locally evolved heritable traits could spread through most of the Lake Albert populations, it seems unlikely they could quickly homogenise into Lake Victoria or amongst populations therein.
Low diversity and high intra-island variation in prevalence of avianHaemoproteusparasites on Barbados, Lesser Antilles
Authors: MARIA L. , SVENSSON E. , RICKLEFS ROBERT E.
Published: July 2009

Common bird species were screened during May and June 2007 on Barbados for haemosporidian parasites (Haemosporida) of the generaHaemoproteusandPlasmodiumto determine whether the low parasite diversity reported in previous studies might have reflected limited sampling. PCR screening and DNA sequencing revealed a single predominant lineage ofHaemoproteusidentified asH. coatneyi. Sixty-two out of 257 birds were infected withHaemoproteusspp. on Barbados in 2007. Fifty-nine of the infections were identified asH. coatneyi(lineage HC), the only lineage recovered in the previous study in 1993. Two of the infections recovered from the bananaquit (Coereba flaveola) were identified asHaemoproteusspp. (lineage HD), which is the prevalent haemosporidian parasite inC. flaveolaon Grenada. We discuss the possibility of infrequent colonization events and absence of vectors as explanations for Barbados's low avian haemosporidian diversity. In our study, the parasites were absent from the southeast of the island, whereas they were abundant in several host species in the northwest. Accordingly, environmental and host population genetic differences were also investigated between the areas with and without parasites. No host genetic differences were found between the parasite-free and the parasite-afflicted regions. However, the parasite-free region is slightly warmer and drier, and it supports less vegetation than the parasite-afflicted region. The influence that this harsher environment may have on vector survival is discussed.
Quitting smoking does not increase the risk of major depressive episodes among users of Internet smoking cessation interventions
Authors: Torres L. D. , Barrera A. Z. , Delucchi K. , Penilla C. , Pérez-Stable E. J. , Muñoz R. F.
Published: July 2009

Background

Limited evidence has suggested that quitting smoking increases the incidence of major depressive episodes (MDEs), particularly for smokers with a history of depression. Further evidence for this increase would have important implications for guiding smoking cessation.

Method

Spanish- and English-speaking smokers without a current MDE (n=3056) from an international, online smoking cessation trial were assessed for abstinence 1 month after their initial quit date and followed for a total of 12 months. Incidence of screened MDE was examined as a function of abstinence and depression history.

Results

Continued smoking, not abstinence, predicted MDE screened at 1 month [smoking 11.5% v. abstinence 7.8%, odds ratio (OR) 1.36, 95% confidence interval (CI) 1.04–1.78, p=0.02] but not afterwards (smoking 11.1% v. abstinence 9.8%, OR 1.05, 95% CI 0.77–1.45, p=0.74). Depression history predicted MDE screened at 1 month (history 17.1% v. no history 8.6%, OR 1.71, 95% CI 1.29–2.27, p<0.001) and afterwards (history 21.7% v. no history 8.3%, OR 3.87, 95% CI 2.25–6.65, p<0.001), although the interaction between history and abstinence did not.

Conclusions

Quitting smoking was not associated with increased MDE, even for smokers with a history of depression, although a history of depression was. Instead, not quitting was associated with increased MDE shortly following a quit attempt. Results from this online, large, international sample of smokers converge with similar findings from smaller, clinic-based samples, suggesting that in general, quitting smoking does not increase the incidence of MDEs.
A simpler definition of major depressive disorder
Authors: Zimmerman M. , Galione J. N. , Chelminski I. , McGlinchey J. B. , Young D. , Dalrymple K. , Ruggero C. J. , Witt C. Francione
Published: July 2009

Background

The DSM-IV symptom criteria for major depressive disorder (MDD) are somewhat lengthy, with many studies showing that treatment providers have difficulty recalling all nine symptoms. Moreover, the criteria include somatic symptoms that are difficult to apply in patients with medical illnesses. In a previous report, we developed a briefer definition of MDD that was composed of the mood and cognitive symptoms of the DSM-IV criteria, and found high levels of agreement between the simplified and full DSM-IV definitions. The goal of the present study was to replicate these findings in another large sample of psychiatric out-patients and to extend the findings to other patient samples.

Method

We interviewed 1100 psychiatric out-patients and 210 pathological gamblers presenting for treatment and 1200 candidates for bariatric surgery. All patients were interviewed by a diagnostic rater who administered a semi-structured interview. We inquired about all symptoms of depression for all patients.

Results

In all three samples high levels of agreement were found between the DSM-IV and the simpler definition of MDD. Summing across all 2510 patients, the level of agreement between the two definitions was 95.5% and the κ coefficient was 0.87.

Conclusions

After eliminating the four somatic criteria from the DSM-IV definition of MDD, a high level of concordance was found between this simpler definition and the original DSM-IV classification. This new definition offers two advantages over the current DSM-IV definition – it is briefer and it is easier to apply with medically ill patients because it is free of somatic symptoms.
Differential predictions about future negative events in seasonal and non-seasonal depression
Authors: Dalgleish T. , Golden A.-M. J. , Yiend J. , Dunn B. D.
Published: July 2009

Background

Previous research indicates that individuals with seasonal depression (SD) do not exhibit the memory biases for negative self-referent information that characterize non-seasonal depression (NSD). The current study extended this work by examining processing of self-referent emotional information concerning potential future events in SD.

Method

SD and NSD patients, along with never-depressed controls, completed a scenario-based measure of likelihood estimation for future positive and negative events happening either to the self or to another person.

Results

SD patients estimated future negative events as more likely to happen to both the self and others, relative to controls. In contrast, in the NSD sample this bias was specific to self-referred material. There were no group differences for positive events.

Conclusions

These data provide further evidence that the self-referent bias for processing negative information that characterizes NSD can be absent in SD, this time in the domain of future event processing.
Neuroimaging in cannabis use: a systematic review of the literature
Authors: Martín-Santos R. , Fagundo A. B. , Crippa J. A. , Atakan Z. , Bhattacharyya S. , Allen P. , Fusar-Poli P. , Borgwardt S. , Seal M. , Busatto G. F. , McGuire P.
Published: July 2009

Background

We conducted a systematic review to assess the evidence for specific effects of cannabis on brain structure and function. The review focuses on the cognitive changes associated with acute and chronic use of the drug.

Method

We reviewed literature reporting neuroimaging studies of chronic or acute cannabis use published up until January 2009. The search was conducted using Medline, EMBASE, LILACS and PsycLIT indexing services using the following key words: cannabis, marijuana, delta-9-tetrahydrocannabinol, THC, cannabidiol, CBD, neuroimaging, brain imaging, computerized tomography, CT, magnetic resonance, MRI, single photon emission tomography, SPECT, functional magnetic resonance, fMRI, positron emission tomography, PET, diffusion tensor MRI, DTI-MRI, MRS and spectroscopy.

Results

Sixty-six studies were identified, of which 41 met the inclusion criteria. Thirty-three were functional (SPECT/PET/fMRI) and eight structural (volumetric/DTI) imaging studies. The high degree of heterogeneity across studies precluded a meta-analysis. The functional studies suggest that resting global and prefrontal blood flow are lower in cannabis users than in controls. The results from the activation studies using a cognitive task are inconsistent because of the heterogeneity of the methods used. Studies of acute administration of THC or marijuana report increased resting activity and activation of the frontal and anterior cingulate cortex during cognitive tasks. Only three of the structural imaging studies found differences between users and controls.

Conclusions

Functional neuroimaging studies suggest a modulation of global and prefrontal metabolism both during the resting state and after the administration of THC/marijuana cigarettes. Minimal evidence of major effects of cannabis on brain structure has been reported.
The evaluation of training in patient-centred interviewing skills for psychiatric residents
Authors: Rimondini M. , Del Piccolo L. , Goss C. , Mazzi M. , Paccaloni M. , Zimmermann C.
Published: July 2009

Background

Communication skills are considered ‘core skills’ in the curriculum of psychiatry but studies evaluating the effectiveness of a time-limited training course in interviewing skills in psychiatry have remained rare. The aim was to assess the effectiveness of training in patient-centred interviewing on the interview performance of psychiatric residents.

Method

Psychiatric residents (n=10) each interviewed 12 different anonymized standardized patients (SPs), eight before and another four after training. SPs simulated psychiatric out-patients who attended for a first visit to the psychiatric out-patient clinic. The consultations were videotaped, transcribed and coded with a classification scheme developed for psychiatric consultations from which an interview performance index was derived. An interrupted time-series design and a segmented regression analysis with multilevel analysis explored the performance trend within the series of consultations.

Results

The regression model evidenced a horizontal slope at pre- and post-training, with a significant level change. These findings excluded the presence of a practice effect and indicated a significant effect of training. Performance variability between and within residents over the series of consultations increased at post-training.

Conclusions

The training improved patient-centred interviewing performance. More post-training exercise time and supervised practice are necessary to establish consistent performance patterns at a higher skill level.
Seismic evidence for Neogene and active shortening offshore of Lebanon (Shalimar cruise)
Authors: Carton H. , Singh S. C. , Tapponnier P. , Elias A. , Briais A. , Sursock A. , Jomaa R. , King G. C. P. , Daëron M. , Jacques E. , Barrier L.
Published: July 2009

Lebanon, located on a 160‐km‐long transpressional bend of the left‐lateral Levant (Dead Sea) fault system (LFS), has been the site of infrequent but large earthquakes, including one submarine, tsunamigenic event. The main objective of the Shalimar marine survey was to characterize and map active deformation offshore of Lebanon using a range of geophysical techniques, particularly seismic reflection profiling. The cruise results clearly establish the presence of young submarine thrust faults and folds and clarify the structure of this part of the Levant margin. A submarine fold belt, bounded by thrusts and lateral ramps and extending up to 30 km from the shoreline, is interpreted as the foreland thrust system of the actively growing Mount Lebanon range. There is no large fault extending into the Levant basin toward Cyprus, which indicates that thrusting only absorbs local transpression resulting from the Lebanese restraining bend. Both the Miocene and Plio‐Quaternary sedimentary sequences are affected by shortening, with landward dipping blind thrusts and associated growth strata. The presence of the Messinian evaporites creates complex deformation patterns, including normal faults due both to folding accommodation and to gravity spreading, all well imaged in the seismic reflection profiles. Because the evaporite layer acts as a décollement level, shortening extends farther out seaward through a series of thrust imbricates or duplexes. The strongest shortening, observed between Beirut and Batroun, decreases toward the south between Saida and Tyre. North of Tripoli, the passive margin is not affected by Neogene deformation and is well preserved. We propose that since the Miocene, the northward propagating LFS interacted with margin structures inherited from the Mesozoic rifting phase and was deviated along the more rigid oceanic crust flooring the Levant basin, a process which led to the formation of the Lebanese restraining bend of the LFS and consequently to the offshore shortening we document here. Such coastal transpression has resulted in local (∼100 km) inversion of the passive margin, which might eventually evolve into a new subduction zone.
Influence of a buoyant river plume on phytoplankton nutrient dynamics: What controls standing stocks and productivity?
Authors: Kudela Raphael M. , Peterson Tawnya D.
Published: July 2009

The influence of the Columbia River plume on phytoplankton rates and biomass accumulation was examined using multiday deckboard incubations as part of the coastal ocean processes River Influences on Shelf Ecosystems field program in August 2005. At a set of five stations encompassing the near‐field plume (three stations) on the Oregon and Washington coasts, treatments consisting of control, added nitrate, and added nitrate with 0.45 μm filtered plume water were used to assess the phytoplankton community response to macronutrients and micronutrients. For a subset of these stations, nutrient (nitrate, ammonium, and ammonium inhibition of nitrate) kinetics were obtained, as well as carbon‐based estimates of productivity. For all experiments, nitrogen (nitrate) was clearly controlling both biomass accumulation and growth rates. Despite the apparent poleward trend toward increasing biomass in this region, there were no obvious differences in phytoplankton physiological capacity, nor were there any symptoms of iron limitation in the short term. We conclude that phytoplankton in this region are predominantly nitrogen limited but that upon release from this limiting factor, phosphorous and/or silicic acid (in waters not influenced by the Columbia River plume) would quickly become limiting. Evidence suggests that the mesoscale differences in phytoplankton biomass between the Oregon and Washington coasts result from a combination of enhanced grazing downstream and the physically retentive and dispersive effects of the plume itself.
Spatial variation in seabed temperatures in the Southern Ocean: Implications for benthic ecology and biogeography
Authors: Clarke Andrew , Griffiths Huw J. , Barnes David K. A. , Meredith Michael P. , Grant Susie M.
Published: July 2009

The Antarctic seabed has traditionally been regarded as cold and thermally stable, with little spatial or seasonal variation in temperature. Here we demonstrate marked spatial variations in continental shelf seabed temperature around Antarctica, with the western Antarctic Peninsula shelf significantly warmer than shelves around continental Antarctica as a result of flooding of the shelf by Circumpolar Deep Water from the Antarctic Circumpolar Current. The coldest shelf seabed temperatures are in the Weddell Sea, Ross Sea, and Prydz Bay as a consequence of seasonal convection associated with strong air‐sea heat fluxes and sea‐ice formation. These waters constitute the dense precursors of Antarctic Bottom Water, and can descend down the adjacent slope to inject cold water into the Southern Ocean deep sea. Deep sea seabed temperatures are coldest in the Weddell Sea and are progressively warmer to the east. There is a distinct latitudinal gradient in the difference between seabed temperatures on the shelf and in the deep sea, with the deep sea warmer by up to ∼2 K at high latitudes and colder by ∼2 K around sub‐Antarctic islands. These differences have important consequences for benthic ecology and biogeography, understanding the evolutionary history of the Antarctic marine biota, and the impact of regional climate change.
Behavior of the O+/H+ transition height during the extreme solar minimum of 2008
Authors: Heelis R. A. , Coley W. R. , Burrell A. G. , Hairston M. R. , Earle G. D. , Perdue M. D. , Power R. A. , Harmon L. L. , Holt B. J. , Lippincott C. R.
Published: July 2009

Typically the solar radio emission at 10.7 cm is used to scale the critical euv radiation that is absorbed by the Earth's neutral atmosphere. In the latter half of 2008 this radio emission from the Sun was at the lowest levels seen in the last 50 years and the persistence of these low levels has never been recorded before. Here we show that these uniquely low levels of solar radiation produce similarly unique behavior in the Earth's ionosphere and the upper atmosphere. Most remarkably, the altitude extent of the ionosphere is significantly smaller than our present reference models would predict for these levels of solar activity. The transition height resides near 450 km at night and rises to only 850 km during the daytime. At night, this unusually contracted ionospheric shell around the equator has a temperature of only 600 K and prior to sunrise the ion number densities at the transition height fall below 104 cm−3.
Freshwater transport from the Pacific to the Bering Sea through Amukta Pass
Authors: Ladd Carol , Stabeno Phyllis J.
Published: July 2009

Flow through the Aleutian Passes connects the North Pacific to the Bering Sea and ultimately the Arctic. Moorings spanning the width of Amukta Pass, deployed 2001–2008, allow quantitative assessment of volume and freshwater transports. Volume transport through Amukta Pass averages 4.7 Sv, with maximum transport in January, minimum in September, and a secondary maximum in July. Average freshwater transport through Amukta Pass is ∼5800 km3 yr−1 with a seasonal cycle similar to that of volume transport. Combining this estimate with first‐order estimates of freshwater transports in the other eastern passes in the Aleutian chain suggests that total freshwater transport is more than five times the cross‐shelf flux of freshwater needed to supply transport through Bering Strait into the Arctic. Ongoing measurements in the Aleutian Passes are critical to understanding the influence of these waters on the Bering Sea and the Arctic Ocean.
Effective pressure law for permeability of E‐bei sandstones
Authors: Li M. , Bernabé Y. , Xiao W.‐I. , Chen Z.‐Y. , Liu Z.‐Q.
Published: July 2009

Laboratory experiments were conducted to determine the effective pressure law for permeability of tight sandstone rocks from the E‐bei gas reservoir, China. The permeability k of five core samples was measured while cycling the confining pressure pc and fluid pressure pf. The permeability data were analyzed using the response‐surface method, a statistical model‐building approach yielding a representation of k in (pc, pf) space that can be used to determine the effective pressure law, i.e., peff = pc − κpf. The results show that the coefficient κ of the effective pressure law for permeability varies with confining pressure and fluid pressure as well as with the loading or unloading cycles (i.e., hysteresis effect). Moreover, κ took very small values in some of the samples, even possibly lower than the value of porosity, in contradiction with a well‐accepted theoretical model. We also reanalyzed a previously published permeability data set on fissured crystalline rocks and found again that the κ varies with pc but did not observe κ values lower than 0.4, a value much larger than porosity. Analysis of the dependence of permeability on effective pressure suggests that the occurrence of low κ values may be linked to the high‐pressure sensitivity of E‐bei sandstones.
A novel radiocarbon dating technique applied to an ice core from the Alps indicating late Pleistocene ages
Authors: Jenk Theo M. , Szidat Sönke , Bolius David , Sigl Michael , Gäggeler Heinz W. , Wacker Lukas , Ruff Matthias , Barbante Carlo , Boutron Claude F. , Schwikowski Margit
Published: July 2009

Ice cores retrieved from high‐altitude glaciers are important archives of past climatic and atmospheric conditions in midlatitude and tropical regions. Because of the specific flow behavior of ice, their age‐depth relationship is nonlinear, preventing the application of common dating methods such as annual layer counting in the deepest and oldest part. Here we present a new approach and technique, allowing dating of any such ice core at arbitrary depth for the age range between ∼500 years B.P. and the late Pleistocene. This new, complementary dating tool has great potential for numerous ice core related paleoclimate studies since it allows improvement and extension of existing and future chronologies. Using small to ultrasmall sample size (100 μg > carbon content > 5 μg) accelerator mass spectrometry, we take advantage of the ice‐included, water‐insoluble organic carbon fraction of carbonaceous aerosols for radiocarbon (14C) dating. Analysis and dating of the bottom ice of the Colle Gnifetti glacier (Swiss‐Italian Alps, 45°55′50″N, 7°52′33″E, 4455 m asl) has been successful in a first application, and the results revealed the core to cover most of the Holocene at the least with indication for late Pleistocene ice present at the very bottom.
Neural Mechanisms Associated With Food Motivation in Obese and Healthy Weight Adults
Authors: Martin Laura E. , Holsen Laura M. , Chambers Rebecca J. , Bruce Amanda S. , Brooks William M. , Zarcone Jennifer R. , Butler Merlin G. , Savage Cary R.
Published: July 2009

One out of three adults in the United States is clinically obese. Excess food intake is associated with food motivation, which has been found to be higher in obese compared to healthy weight (HW) individuals. Little is known, however, regarding the neural mechanisms associated with food motivation in obese compared to HW adults. The current study used functional magnetic resonance imaging (fMRI) to examine changes in the hemodynamic response in obese and HW adults while they viewed food and nonfood images in premeal and postmeal states. During the premeal condition, obese participants showed increased activation, compared to HW participants, in anterior cingulate cortex (ACC) and medial prefrontal cortex (MPFC). Moreover, in the obese group, self‐report measures of disinhibition were negatively correlated with premeal ACC activations and self‐report measures of hunger were positively correlated with premeal MPFC activations. During the postmeal condition, obese participants also showed greater activation than HW participants in the MPFC. These results indicate that brain function associated with food motivation differs in obese and HW adults and may have implications for understanding brain mechanisms contributing to overeating and obesity, and variability in response to diet interventions.
Excess Weight and the Risk of Incident Coronary Heart Disease Among Men and Women
Authors: Flint Alan J. , Hu Frank B. , Glynn Robert J. , Caspard Hervé , Manson JoAnn E. , Willett Walter C. , Rimm Eric B.
Published: July 2009

Overweight and obesity have been prospectively associated with the risk of coronary heart disease (CHD). Less clear is the relation of excess weight to risk of CHD among men and women with comorbid conditions, and the proportion of CHD risk attributable to excess weight in the US population. To assess the risk of CHD associated with excess weight among men and women with and without associated comorbid conditions, and determine the population attributable risk of CHD associated with excess weight. The study population consisted of two prospective cohorts, the Health Professionals Follow‐up Study (HPFS) (N = 42,351 men; age range at baseline, 39–75 years) and the Nurses' Health Study (NHS) (N = 76,703 women; age range at baseline, 39–65 years). A total of 2,771 incident cases of CHD among the men and 2,359 among the women were documented over the 16 years of follow‐up. Overall, the relative risk (RR) of CHD associated with BMI ≥30 kg/m2 compared with BMI 18.5–22.9 kg/m2 was 2.13 (95% confidence interval (CI), 1.82–2.48) among the men and 2.48 (95% CI, 2.20–2.80) among the women. The risk of CHD increased with BMI, both with and without the presence of comorbid conditions. Our estimates suggest that more than a third of all incident CHD in US men and women may be attributed to excess weight. Excess weight is associated with increased risk of CHD among men and women, both alone and in combination with comorbid conditions, though the results require careful interpretation. A substantial proportion of incident CHD may be attributed to excess weight.
Relationship Between Body Fat Mass and Free Fatty Acid Kinetics in Men and Women
Authors: Mittendorfer Bettina , Magkos Faidon , Fabbrini Elisa , Mohammed B. Selma , Klein Samuel
Published: July 2009

An increased release of free fatty acids (FFAs) into plasma likely contributes to the metabolic complications associated with obesity. However, the relationship between body fat and FFA metabolism is unclear because of conflicting results from different studies. The goal of our study was to determine the inter‐relationships between body fat, sex, and plasma FFA kinetics. We determined FFA rate of appearance (Ra) in plasma, by using stable isotopically labeled tracer techniques, during basal conditions in 106 lean, overweight, and obese, nondiabetic subjects (43 men and 63 women who had 7.0–56.0% body fat). Correlation analyses demonstrated: (i) no differences between men and women in the relationship between fat mass (FM) and total FFA Ra (µmol/min); (ii) total FFA Ra increased linearly with increasing FM (r = 0.652, P < 0.001); (iii) FFA Ra per kg FM decreased in a curvilinear fashion with increasing FM (r = −0.806; P < 0.001); (iv) FFA Ra in relationship to fat‐free mass (FFM) was greater in obese than lean subjects and greater in women than in men; and (v) abdominal fat itself was not an important determinant of total FFA Ra. We conclude that total body fat, not regional fat distribution or sex, is an important modulator of the rate of FFA release into plasma. Although increased adiposity is associated with a decrease in fatty acid release in relationship to FM, this downregulation is unable to completely compensate for the increase in FM, so total FFA Ra and FFA Ra with respect to FFM are greater in women than in men and in obese than in lean subjects.
Form and flexibility in phosphoinositide 3-kinases
Authors: Williams Roger , Berndt Alex , Miller Simon , Hon Wai-Ching , Zhang Xuxiao
Published: July 2009

PI3Ks (phosphoinositide 3-kinases) have important roles in a variety of cellular activities, including survival, proliferation, growth, shape, migration and intracellular sorting. Consistent with their function in cell survival and growth, the gene for the class Iα PI3K catalytic subunit is a common site of gain-of-function mutations in cancers. Ongoing structural studies of these enzymes and the complexes they make with their regulatory subunits have helped to clarify the mechanistic basis of this role in tumour development. The broad spectrum of biological activities associated with various isotypes of class I PI3Ks has led to an intense search for isotype-specific inhibitors as tools in mammalian cell biology and for therapeutic application. Structural studies of the class I PI3Ks suggest that flexibility may be a component of the catalytic cycle of the enzymes.
Engineering responsive mechanisms to control the assembly of peptide-based nanostructures
Authors: Dublin Steven , Zimenkov Yuri , Conticello Vincent P.
Published: July 2009

Complex biological machines arise from self-assembly on the basis of structural features programmed into sequence-specific macromolecules (i.e. polypeptides and polynucleotides) at the molecular level. As a consequence of the near-absolute control of macromolecular architecture that results from such sequence specificity, biological structural platforms may have advantages for the creation of functional supramolecular assemblies in comparison with synthetic polymers. Thus biological structural motifs present an attractive target for the synthesis of artificial nanoscale systems on the basis of relationships between sequence and supramolecular structure that have been established for native biological assemblies. In the present review, we describe an approach to the creation of structurally defined supramolecular assemblies derived from synthetic α-helical coiled-coil structural motifs. Two distinct challenges are encountered in this approach to materials design: the ability to recode the canonical sequences of native coiled-coil structural motifs to accommodate the formation of structurally defined supramolecular assemblies (e.g. synthetic helical fibrils) and the development of methods to control supramolecular self-assembly of these peptide-based materials under defined conditions that would be amenable to conventional processing methods. In the present review, we focus on the development of mechanisms based on guest–host recognition to control fibril assembly/disassembly. This strategy utilizes the latent structural specificity encoded within sequence-defined peptides to couple a conformational transition within the coiled-coil motifs to incremental changes in environmental conditions. The example of a selective metal-ion-induced conformational switch will be employed to validate the design principles.
Controlling stiffness in nanostructured hydrogels produced by enzymatic dephosphorylation
Authors: Thornton Kate , Smith Andrew M. , Merry Catherine L.R. , Ulijn Rein V.
Published: July 2009

In the present paper, we report on enzyme-initiated self-assembly of Fmoc (fluoren-9-ylmethoxycarbonyl)–tyrosine hydrogels by enzymatic dephosphorylation under physiological conditions and provide evidence for the ability to control the modulus. Upon enzyme action, a self-assembling network of interconnecting fibres is formed, observed by cryo-SEM (scanning electron microscopy) and TEM (transmission electron microscopy). The concentration of alkaline phosphatase added to the Fmoc–tyrosine phosphate ester precursor solution had a direct effect on the gelation time, mechanical properties and molecular arrangements as determined through oscillatory rheology, fluorescence spectroscopy and CD spectroscopy. This highly tuneable cost-effective gel system may have applications in three-dimensional cell culture.
Protein aggregation: more than just fibrils
Authors: Krebs Mark R.H. , Domike Kristin R. , Donald Athene M.
Published: July 2009

The aggregation of misfolded proteins into amyloid fibrils, and the importance of this step for various diseases, is well known. However, it is becoming apparent that the fibril is not the only structure that aggregating proteins of widely different types may adopt. Around the isoelectric point, when the net charge is essentially zero, rather monodisperse and quasi-amorphous nanoscale particles form. These particles are found to contain limited runs of β-sheet structure, but their overall organization is random. These nanoparticles have the potential to be useful for such applications as the slow release of drugs. The amyloid fibrils form away from the isoelectric point, but over certain ranges of, e.g., pH, the fibrils themselves do not exist freely, but form suprafibrillar aggregates termed spherulites. These consist of fibrils radiating from a central nucleus, and form by new species attaching to the ends of growing fibrils, rather than by the aggregation of pre-existing fibrils. Under the polarizing light microscope, they exhibit a Maltese cross shape due to their symmetry. The rate of aggregation is determined by factors involving (at least) protein size, concentration, presence of salt and charge. The occurrence of spherulites, which have been found in vivo as well as in vitro, appears to be generic, although the factors which determine the equilibrium between free fibril and spherulite are not as yet clear.
Applications of nanopipettes in bionanotechnology
Authors: Ying Liming
Published: July 2009

At present, technical hurdles remain in probing biochemical processes in living cells and organisms at nanometre spatial resolution, millisecond time resolution and with high specificity and single-molecule sensitivity. Owing to its unique shape, size and electrical properties, the nanopipette has been used to obtain high-resolution topographic images of live cells under physiological conditions, and to create nanoscale features by controlled delivery of biomolecules. In the present paper, I discuss recent progress in the development of a family of new methods for nanosensing and nanomanipulation using nanopipettes.
Sterically stabilized self-assembling reversibly cross-linked polyelectrolyte complexes with nucleic acids for environmental and medical applications
Authors: Garnett Martin C. , Ferruti Paolo , Ranucci Elisabetta , Suardi Marco A. , Heyde Mieke , Sleat Rob
Published: July 2009

One of the principal problems facing nucleic acid delivery systems using polyplexes is the instability of the complexes in the presence of proteins and high salt concentrations. We have used a cross-linking polymer to overcome this problem. Pendant thiol moieties have been incorporated into a PAA (polyamidoamine) homopolymer and a PEG [poly(ethylene glycol)]–PAA–PEG copolymer reported previously as a self-assembling system. When mixed with DNA, small monodisperse sterically stabilized particles are formed in quantitative yields. Optimization of the formulation resulted in nanoparticles which are stable in seawater. This cross-linked formulation has been successfully tested in both freshwater and estuarine field trials as a water tracer. Future work will develop these particles as a groundwater tracer and also for therapeutic applications of nucleic acid delivery.
The evolution of protein functions and networks: a family-centric approach
Authors: Dessailly Benoît H. , Reid Adam J. , Yeats Corin , Lees Jonathan G. , Cuff Alison , Orengo Christine A.
Published: July 2009

The study of superfamilies of protein domains using a combination of structure, sequence and function data provides insights into deep evolutionary history. In the present paper, analyses of functional diversity within such superfamilies as defined in the CATH-Gene3D resource are described. These analyses focus on structure–function relationships in very large and diverse superfamilies, and on the evolution of domain superfamily members in protein–protein complexes.