bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal MAV operations in an uncertain environment
Authors: Pachter Meir , Chandler Phillip R. , Darbha Swaroop
Published: May 2007

In this paper, we consider a problem of sequential resource allocation. Such a problem arises in a simplified intelligence, surveillance and reconnaissance scenario where a micro air vehicle (MAV) is tasked with classification in an environment with false, that is, clutter, targets. The MAV visits the objects of interest in a specified sequence. A human operator is tasked with aiding the MAV's automatic target recognition system with the classification of objects, based on the images sent to him from the MAVs. If the images do not resolve the ambiguity concerning the status of the object being classified, the operator may request that the object be revisited. In this paper, for the sake of exposition of the employed methods and clarity of presentation, we assume that every object may be revisited at most once. Each object can be revisited and re‐examined in L⩾ 1 ways. There is an information gain whose value is given by the running reward. The information gain depends on the way an object is re‐examined, and the feedback from the operator but it is the same for all the objects. There is a random operator delay in communicating his findings to the MAV and the probability density function of the delay is assumed known. The MAV has a limited fuel reserve and upon getting feedback from the operator (and hence, knowing the delay associated with the object of interest only and not with those that it must revisit in the future), it must decide whether to revisit the object and if so, which of the L ways is optimal so as to maximize the total expected reward. In every revisit, fuel is expended from the reserve and is proportional to twice the delay plus a fixed cost, which is dependent on the way in which the object is re‐examined. We employ a stochastic dynamic programming approach to solve this problem. Specifically, for the case when L = 1, we show that there is an optimal threshold for each object and it is optimal to revisit the object if the delay is at most the threshold and not to revisit otherwise. For the case when L > 1, the structure of the optimal decision algorithm is not as simple, but it can be computed off‐line so as to facilitate its real‐time implementation. Published in 2007 by John Wiley & Sons, Ltd.
A nonlinear model predictive control approach for robust end‐point property control of a thin‐film deposition process
Authors: Nagy Zoltán K. , Allgöwer Frank
Published: May 2007

Although an increasing number of simulation and experimental evaluation studies show the advantages of nonlinear model predictive control (NMPC), generally in practice processes are operated using open‐loop input and reference trajectories. NMPC strategies can address explicitly constraints and nonlinearities during the feedback control of batch processes. However, the control performance is strongly dependent on the quality of the model used in the controller. Although generally in the nominal case good performance can be achieved, disturbances and model uncertainties can have drastic influence on the control performance, and might even lead to instability. The paper presents an NMPC algorithm that explicitly takes parameter uncertainty into account in the controller designs. The shrinking horizon NMPC algorithm minimizes a weighted sum of the nominal performance objective, an estimate of the variance of the performance objective, and an integral of the deviation of the control trajectory from the nominal optimal control trajectory. The robust performance is quantified by estimates of the distribution of the performance index along the batch run obtained by a power series expansion about the control trajectory. The potential advantages of the proposed robust NMPC in the microelectronics industry are demonstrated using an example process of thin‐film deposition. Copyright © 2007 John Wiley & Sons, Ltd.
Workflows and cooperative processes
Authors: Estublier Jacky , Garcia Sergio
Published: April 2007

Workflows emphasize the partial order of activities, and the flow of data between activities. In contrast, cooperative processes emphasize the sharing of artefact, and its gradual evolution toward the final product, under the cooperative and concurrent activities of all the involved actors.

This article contrasts workflow and cooperative processes and shows that they are more complementary than conflicting and that, provided some extensions, both approaches can fit into a single tool and formalism.

This article presents Celine, a concurrent engineering tool that can also define and support classic workflows and software processes. We claim that the availability of both classes of features allows for the modeling and support of very flexible processes, closer to software engineering reality. Copyright © 2007 John Wiley & Sons, Ltd.
Decreased numerical density of CA3 hippocampal mossy fiber synapses in schizophrenia
Authors: Kolomeets Natalya S. , Orlovskaya Diana D. , Uranova Natalya A.
Published: May 2007

The CA3 region of the hippocampus is unique in its connectivity, its role in cognitive maintenance, and its great vulnerability in schizophrenia. The down regulation of the expression and binding activity of glutamate receptors was revealed in the CA3 hippocampal region and may be attributed to cognitive disturbances in schizophrenia. Our previous study demonstrated that only schizophrenics with predominantly positive (but not predominantly negative) symptoms had smaller‐sized branched spines (thorny excrescences) of CA3 pyramidal neurons and fewer synaptic contacts formed by dentate mossy fiber terminals (MFT‐synapses). In the present study, we used an unbiased stereological physical dissector method to verify whether the numerical density of MFT‐synapses is altered in schizophrenia. A morphometric study was performed in 10 normal controls and eight age‐matched cases with chronic schizophrenia, including five cases with predominantly positive and three with predominantly negative symptoms. Schizophrenic cases had a significantly reduced numerical density of MFT‐synapses (−25%, P < 0.01) compared with the control group. The decrease was similar in schizophrenic subgroups with predominantly positive and predominantly negative symptoms. No effects of postmortem delay, age, duration of disease, and neuroleptic exposure were found. Taken together with our previous results, the data suggest that the decrease of numerical density of MFT‐synapses may be the result of different mechanisms in schizophrenics with predominantly positive and predominantly negative symptoms. Synapse 61:615–621, 2007. © 2007 Wiley‐Liss, Inc.
Comparison between magnetic resonance imaging and fetopathology in the evaluation of fetal posterior fossa non‐cystic abnormalities
Authors: Tilea B. , Delezoide A. L. , Khung‐Savatovski S. , Guimiot F. , Vuillard E. , Oury J. F. , Garel C.
Published: May 2007

Objectives

To compare magnetic resonance imaging (MRI) and fetopathological findings in the evaluation of non‐cystic fetal posterior fossa anomalies and to describe associated abnormalities.

Methods

This was a prospective study from 2000 to 2005 of fetuses identified on ultrasound as having sonographic suspicion of posterior fossa malformation. All underwent a thorough MRI examination of the fetal brain, after which we classified each fetus as presenting one of the following pathologies: vermian hypoplasia or agenesis, cerebellar and/or brain stem hypoplasia, destructive or dysplastic lesions. All of the pregnancies were then terminated, after which the whole fetus underwent fetopathological examination. We compared the findings from MRI and fetopathological examinations and recorded the associated cerebral and extracerebral abnormalities.

Results

Twenty‐five fetuses were included. MRI was performed at a mean gestational age of 31 weeks, and fetopathological examination at 33 weeks. In 12 cases we observed vermian hypoplasia, six had partial vermian agenesis, 11 had cerebellar hemisphere hypoplasia, seven had brain stem hypoplasia, four had destructive lesions and six had dysplastic lesions. The two techniques were similar in their performance with respect to the detection of vermian agenesis, brain stem hypoplasia and destructive lesions. There were four false‐positive results of MRI for vermian hypoplasia and a poor agreement regarding cerebellar hemisphere hypoplasia. No dysplastic lesions were diagnosed by MRI. None of the posterior fossa malformations was isolated and many cerebral and extracerebral abnormalities were found.

Conclusion

A systematic analysis of the posterior fossa in fetal MRI makes it possible to diagnose accurately most posterior fossa malformations. These malformations never occurred in isolation in our study. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Z‐scores of the fetal aortic isthmus and duct: an aid to assessing arch hypoplasia
Authors: Pasquini L. , Mellander M. , Seale A. , Matsui H. , Roughton M. , Ho S. Y. , Gardiner H. M.
Published: May 2007

Objective

Prenatal diagnosis of isolated coarctation of the aorta suffers from high false positive and false negative rates. The aim of our study was to develop Z‐scores for the aortic isthmus in normal fetuses as a reference for fetuses with suspected coarctation.

Methods

The aortic isthmal diameter, immediately proximal to the insertion of the arterial duct, was measured prospectively in the transverse (three vessel and trachea) and sagittal views in 221 normal fetuses at 18 to 37 weeks' gestation. The ductal diameter was measured immediately before it entered the descending aorta in the same view. All measurements were repeated three times by a single investigator and averaged. A second investigator re‐measured the images of 50 cases to assess interobserver variability. Z‐scores were created relating isthmal and ductal diameters to femur length and gestational age. The ratio between the isthmal and ductal diameters was calculated.

Results

The formula used to calculate Z‐scores for the three diameters was: [ln(measured isthmal diameter) − (m ln(femur length or gestational age) + c)]/root MSE, where c is the intercept, m is a multiplier and MSE is the mean squared error. The ratio between isthmal and ductal diameters was close to a constant value of 1 (95% CI 0.97–1.01), regardless of the value of femur length or gestational age.

Conclusion

We have defined Z‐scores for the fetal aortic isthmus and arterial duct measured in the three vessels and trachea view and for the isthmus in the sagittal plane. In suspected coarctation, these Z‐scores and the isthmal to ductal ratio may help in longitudinal assessment of the aortic arch and aid in the prenatal diagnosis of coarctation. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Fetal thymus size as a predictor of chorioamnionitis in women with preterm premature rupture of membranes
Authors: Yinon Y. , Zalel Y. , Weisz B. , Mazaki‐Tovi S. , Sivan E. , Schiff E. , Achiron R.
Published: April 2007

Objective

Emerging evidence indicates that chorioamnionitis is associated with a significant decrease in thymic size at birth in very low birth weight (VLBW) preterm infants. The aim of this study was to determine whether decreased fetal thymus size is associated with histological or clinical chorioamnionitis in patients with preterm premature rupture of membranes (PROM).

Methods

Twenty‐one patients between 24 and 35 weeks of gestation with preterm PROM were included. Serial ultrasound examinations were performed during the latency period, and measurements of the fetal thymus size were obtained. Small thymus was defined as a thymus perimeter ≤ 5th percentile according to a fetal thymus nomogram, which was based on measurements of 403 fetuses. Diagnosis of chorioamnionitis was made using neonatal clinical parameters and histological examinations of the placentas.

Results

In our study 13 patients presented with thymus size below the 5th percentile. Among the 13 patients with small thymus, nine (69%) had clinical or histological findings consistent with the diagnosis of chorioamnionitis. All eight women with a normal‐sized thymus had no evidence of clinical or histological chorioamnionitis. Fetal thymus perimeter ≤ 5th percentile yielded a sensitivity of 100%, specificity of 66.7%, a positive predictive value of 69% and a negative predictive value of 100% for identifying chorioamnionitis in patients with preterm PROM.

Conclusions

Fetal thymus size is decreased in women with preterm PROM and chorioamnionitis. Measurement of the fetal thymus might allow an early diagnosis of chorioamnionitis in cases of preterm PROM. Normal thymus size might be used to rule out latent intrauterine infection. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound assessment of pelvic organ prolapse: the relationship between prolapse severity and symptoms
Authors: Dietz H. P. , Lekskulchai O.
Published: April 2007

Objective

At present little information is available to help define whether a certain degree of pelvic organ prolapse is clinically relevant. We performed a retrospective study to define cut‐offs for significant pelvic organ descent on the basis of prolapse symptoms.

Methods

At a tertiary urogynecological center, 735 women with symptoms of lower urinary tract dysfunction and prolapse were seen for interview, clinical examination, multi‐channel urodynamics and ultrasound imaging, while supine and after voiding, for prolapse quantification. Women with multi‐compartment prolapse, i.e. those in whom no compartment was clearly dominant were excluded. Receiver–operator statistics were used to test pelvic organ descent as a predictor of prolapse symptoms.

Results

Mean age was 55.1 years, mean parity 2.8 (range, 0–12). Symptoms of prolapse were reported by 188 women (25.6%). Seventy‐four showed a symptomatic multi‐compartment prolapse and were excluded, 56 symptomatic women had cystoceles and 48 had rectoceles. Symptomatic cystoceles descended on average to 23.8 mm below the symphysis pubis and symptomatic rectoceles to 21.4 mm below the symphysis pubis. Descent was strongly associated with symptoms of prolapse (both, P < 0.001). Receiver–operating characteristics (ROC) statistics suggested a cut‐off of 10 mm below the symphysis pubis for cystocele, and 15 mm below the symphysis pubis for rectocele. ROC curves were similar for both compartments (area under the curve, 0.857 and 0.821, respectively).

Conclusions

Descent of the bladder to ≥ 10 mm and of the rectum to ≥ 15 mm below the symphysis pubis are strongly associated with symptoms, and these values are proposed as cut‐offs for the diagnosis of significant prolapse on the basis of ROC statistics. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Observations on the Use of Seprafilm® on the Brachial Plexus in 249 Operations for Neurogenic Thoracic Outlet Syndrome
Authors: Sanders Richard J. , Hammond Sharon L. , Rao Neal M.
Published: May 2007

Purpose

Seprafilm® was initially used successfully as a membrane to reduce abdominal adhesions. Subsequently it was tried in a number of other areas to reduce postoperative scarring. Seprafilm® was employed in this study to see if it would reduce postoperative scarring after supraclavicular thoracic outlet decompression for neurogenic thoracic outlet syndrome (NTOS).

Material and methods

There were 249 operations for primary NTOS (185) and recurrent NTOS (64). Seprafilm® was applied to the nerve roots at the end of each procedure. Diagnosis was established by careful history and extensive physical exam consisting of several provocative maneuvers. Scalene muscle block confirmed the diagnosis.

Results

Success rates for primary operations, 1–2 years postoperation were 74% for scalenectomy without first rib resection and 70% for scalenectomy with first rib resection. For reoperations, success rate for scalenectomy and neurolysis after transaxillary rib resection was 78% whereas success rate for neurolysis after supraclavicular scalenectomy was 68%. Seprafilm® did not significantly improve overall results compared to our results 15 years ago, although in reoperations there was a trend toward improvement with Seprafilm®. Observations in 10 reoperations after use of Seprafilm® revealed that there were fewer adhesions between fat pad and nerve roots, making it much easier to find the nerve roots. Recurrence was because of scar formation around individual nerve roots.

Conclusion

Seprafilm® made reoperations easier by reducing scarring between scalene fat pad and brachial plexus. However, it did not prevent scar tissue forming around the individual nerve roots nor did it significantly lower the failure rate for primary operations. The trend supported the use of Seprafilm® in reoperations.
Digesta transit in different segments of the gastrointestinal tract of pigs as affected by insoluble fibre supplied by wheat bran
Authors: Wilfart Aurélie , Montagne Lucile , Simmins Howard , Noblet Jean , Milgen Jaap van
Published: April 2007

Digestibility is the result of two competing processes: digestion and digesta transit. To develop or parameterise mechanistic models of digestion, both processes have to be quantified. The aim of this study was to determine the effect of insoluble dietary fibre on the transit in the gastrointestinal tract of pigs. Six barrows (33 kg initial body weight and fitted with two simple T-cannulas at the proximal duodenum and distal ileum) were used in a double 3 × 3 Latin square design. Pigs were offered diets differing in total dietary fibre content (170, 220 and 270 g/kg DM) at 4 h intervals. A single meal marked with YbO2and Cr-EDTA was used to determine the kinetics of markers concentrations of the solid and liquid phases, respectively. The mean retention time (MRT), calculated by the method of the moments, averaged 1, 4 and 38 h in the stomach, small intestine and large intestine, respectively. Increasing the insoluble fibre content in the diet had no effect on MRT in the stomach and decreased the MRT of both phases in the small intestine (P < 0·05). In the large intestine, increasing the insoluble fibre content decreased the MRT of the liquid phase (P = 0·02) and tended to decrease the MRT of the solid phase (P = 0·06). Transit of the solid phase in the large intestine was 4–8 h slower than transit of the liquid phase. Analysis of marker excretion curves indicated that the small and large intestine should be represented mathematically to have both a tubular (propulsion) and compartmental (mixing) structure.
The Labour Process in the Bombay Handloom Industry, 1880–1940
Authors: HAYNES DOUGLAS E.
Published: May 2007

Analyses of capital-labour relations in Indian industry during the colonial period have generally been confined to studies of large-scale units. This essay turns to an examination of the organization of the workplace among handloom producers in the Bombay Presidency during the period between 1880 and 1940. While recognizing the importance of contradictions between weaving families and various kinds of capitalists, the essay eschews any straightforward model of “proletarianization” to characterize this relationship. Weavers possessed methods of resistance, particularly “everyday” actions, which thwarted efforts to impose tight regimes of labour discipline within the workshop. Seeking to contain these resistances, shahukars (putting-out merchants) and karkhandars (owners of establishments using wage labour) developed complex social relationships with their workers based upon patronage, debt, and caste. Consequently, collective protest in the industry was limited, and when it did emerge in Sholapur during the later 1930s, it was highly conditioned and constrained by the multiple lines of affiliation weavers had with karkhandars.
The anthelmintic efficacy of plant-derived cysteine proteinases against the rodent gastrointestinal nematode,Heligmosomoides polygyrus,in vivo
Authors: STEPEK G. , LOWE A. E. , BUTTLE D. J. , DUCE I. R. , BEHNKE J. M.
Published: May 2007

Gastrointestinal (GI) nematodes are important disease-causing organisms, controlled primarily through treatment with synthetic drugs, but the efficacy of these drugs has declined due to widespread resistance, and hence new drugs, with different modes of action, are required. Some medicinal plants, used traditionally for the treatment of worm infections, contain cysteine proteinases known to damage worms irreversiblyin vitro. Here we (i) confirm that papaya latex has marked efficacyin vivoagainst the rodent gastrointestinal nematode,Heligmosomoides polygyrus, (ii) demonstrate the dose-dependent nature of the activity (>90% reduction in egg output and 80% reduction in worm burden at the highest active enzyme concentration of 133 nmol), (iii) establish unequivocally that it is the cysteine proteinases that are the active principlesin vivo(complete inhibition of enzyme activity when pre-incubated with the cysteine proteinase-specific inhibitor, E-64) and (iv) show that activity is confined to worms that are in the intestinal lumen. The mechanism of action was distinct from all current synthetic anthelmintics, and was the same as thatin vitro, with the enzymes attacking and digesting the protective cuticle. Treatment had no detectable side-effects on immune cell numbers in the mucosa (there was no difference in the numbers of mast cells and goblet cells between the treated groups) and mucosal architecture (length of intestinal villi). Only the infected and untreated mice had much shorter villi than the other 3 groups, which was a consequence of infection and not treatment. Plant-derived cysteine proteinases are therefore prime candidates for development as novel drugs for the treatment of GI nematode infections.
In evolutionary games, enlightened self-interests are still ultimately self-interests
Authors: Getty Thomas
Published: May 2007

Evolutionary theory provides a firm foundation for the unification of the behavioral sciences, and the beliefs, preferences, and constraints (BPC) model is a useful analytical tool for understanding human behavior. However, evolutionary theory suggests that if other-regarding preferences expressed by humans have evolved under selection, they are ultimately, if not purely, in the constrained, relative self-interests of individuals who express them.
Gintis meets Brunswik – but fails to recognize him
Authors: Hammond Kenneth R.
Published: May 2007

With a few incisive (and legitimate) criticisms of crucial experiments in psychology that purported to bring down the foundations of modern economics, together with a broad scholarly review that is praiseworthy, Gintis attempts to build a unifying framework for the behavioral sciences. His efforts fail, however, because he fails to break with the conventional methodology, which, regrettably, is the unifying basis of the behavioral sciences. As a result, his efforts will merely recapitulate the story of the past: interesting, provocative results that are soon overthrown because they are limited to the conditions of the experiment. Gintis is keenly aware of this limitation – and thus meets Brunswik, but fails to recognize him; this we know because he seems unaware of the fact that Brunswik said it all – and provided a detailed defense – a half century ago.
Rationality versus program-based behavior
Authors: Hodgson Geoffrey M.
Published: May 2007

For Herbert Gintis, the “rational actor,” or “beliefs, preferences, and constraints (BPC),” model is central to his unifying framework for the behavioral sciences. It is not argued here that this model is refuted by evidence. Instead, this model relies ubiquitously on auxiliary assumptions, and is evacuated of much meaning when applied to both human and nonhuman organisms. An alternative perspective of “program-based behavior” is more consistent with evolutionary principles.
The integrative framework for the behavioural sciences has already been discovered, and it is the adaptationist approach
Authors: Price Michael E. , Brown William M. , Curry Oliver S.
Published: May 2007

The adaptationist framework is necessary and sufficient for unifying the social and natural sciences. Gintis's “beliefs, preferences, and constraints” (BPC) model compares unfavorably to this framework because it lacks criteria for determining special design, incorrectly assumes that standard evolutionary theory predicts individual rationality maximisation, does not adequately recognize the impact of psychological mechanisms on culture, and is mute on the behavioural implications of intragenomic conflict.
Theoretical sequelae of a chronic neglect and unawareness of prefrontotectal pathways in the human brain
Authors: Barceló Francisco , Knight Robert T.
Published: May 2007

Attention research with prefrontal patients supports Merker's argument regarding the crucial role for the midbrain in higher cognition, through largely overlooked and misunderstood prefrontotectal connectivity. However, information theoretic analyses reveal that both exogenous (i.e., collicular) and endogenous (prefrontal) sources of information are responsible for large-scale context-sensitive brain dynamics, with prefrontal cortex being at the top of the hierarchy for cognitive control.
A brain for all seasons
Authors: Gardner R. Allen
Published: May 2007

Merker's fine article opens a new view of brain function consistent with current developments in robotics, heuristics, and fuzzy logic. A reciprocal, tripartite organization of input/motivation/output in the midbrain can accomplish the practical tasks of a brain. A bold move places consciousness in the midbrain, raising profound questions about the practical nature of consciousness.
Consciousness is more than wakefulness
Authors: Morin Alain
Published: May 2007

Merker's definition of consciousness excludes self-reflective thought, making his proposal for decorticate consciousness not particularly ground-breaking. He suggests that brainstem sites are neglected in current theories of consciousness. This is so because broader definitions of consciousness are used. Split-brain data show that the cortex is important for full-blown consciousness; also, behaviors exhibited by hydranencephaly patients and decorticated rats do not seem to require reflective consciousness.
Emotional feelings originate below the neocortex: Toward a neurobiology of the soul
Authors: Panksepp Jaak
Published: May 2007

Disregard of primary-process consciousness is endemic in mind science. Most neuroscientists subscribe to ruthless reductionism whereby mental qualities are discarded in preference for neuronal functions. Such ideas often lead to envisioning other animals, and all too often other humans, as unfeeling zombies. Merker correctly highlights how the roots of consciousness exist in ancient neural territories we share, remarkably homologously, with all the other vertebrates.
The ontology of creature consciousness: A challenge for philosophy
Authors: Piccinini Gualtiero
Published: May 2007

I appeal to Merker's theory to motivate a hypothesis about the ontology of consciousness: Creature consciousness is (at least partially) constitutive of phenomenal consciousness. Rather than elaborating theories of phenomenal consciousness couched solely in terms of state consciousness, as philosophers are fond of doing, a correct approach to phenomenal consciousness should begin with an account of creature consciousness.
Should the superficial superior colliculus be part of Merker's mesodiencephalic system?
Authors: Schlag John
Published: May 2007

The superficial superior colliculus appears to be a primitive visual analyzer whose function has been taken over by the visual cortex, most completely in man. The phenomenon of blindsight shows that, although intact, the superior colliculus cannot by itself provide conscious perception in human patients. Is it possible that, in anencephalic children, it recovers the role it had in lower mammals?
Dynamical systems: stability and simulability
Authors: HOYRUP MATHIEU
Published: May 2007

Computers are used extensively to simulate continuous dynamical systems. However, different conceptual and mathematical structures underlie discrete machines and continuous dynamics, so the question arises as to the ability of the computer to simulate or, more generally, to check the properties of a continuous system.

We discuss and compare two notions of stability for a continuous dynamical system,viz.shadowing and robustness, and relate them to both the practical and theoretical computability of the system. We first discuss what we can learn from the stability of a system, using a finite-precision machine. We then show, following the work in Collins (2005), that shadowing fails but robustness succeeds in ensuring the checkability of a reachability property.
A comparison of the programme coverage of two therapeutic feeding interventions implemented in neighbouring districts of Malawi
Authors: Sadler Kate , Myatt Mark , Feleke Teshome , Collins Steve
Published: April 2007

Objective

To compare therapeutic feeding programme coverage for severely malnourished children achieved by a community-based therapeutic care (CTC) programme and a therapeutic feeding centre (TFC) programme operating in neighbouring districts in Malawi.

Design

Two surveys were implemented simultaneously one in each of the two programme areas. Each survey used a stratified design with strata defined using the centric systematic area sample method. Thirty 100 km2quadrats were sampled. The community or communities located closest to the centre of each quadrat were sampled using a case-finding approach. Cases were defined as children aged under 5 years with ≤ 70% of the weight-for-height median or bilateral pitting oedema. Receipt of treatment was ascertained by the child's presence in a therapeutic feeding programme or by documentary evidence. Coverage in each quadrat was estimated in two ways, a period estimate that provides an estimation of coverage for the recent period preceding the survey and a point estimate that provides an estimation of coverage at the exact point in time of the survey.

Results

Overall the period coverage was 24.55% (95% confidence interval (CI) = 17.8–31.4%) in the TFC programme and 73.64% (95% CI = 66.0–81.3%) in the CTC programme. The point coverage was 20.04% (95% CI = 13.8–26.3%) in the TFC programme and 59.95% (95% CI = 51.4–68.5%) in the CTC programme.

Conclusions

In this context, CTC gave substantially higher programme coverage than a TFC programme. Given effective treatment, this enabled higher impact of CTC on severe malnutrition in this population.
Migration of comets to the terrestrial planets
Authors: Ipatov Sergei I. , Mather John C.
Published: May 2007

We studied the orbital evolution of objects with initial orbits close to those of Jupiter-family comets (JFCs), Halley-type comets (HTCs), and long-period comets, and the probabilities of their collisions with the planets. In our runs the probability of a collision of one object with the Earth could be greater than the sum of probabilities for thousands of other objects. Even without the contribution of such a few objects, the probability of a collision of a former JFC with the Earth during the dynamical lifetime of the comet was greater than 4×10−6. This probability is enough for delivery of all the water to Earth's oceans during the formation of the giant planets. The ratios of probabilities of collisions of JFCs and HTCs with Venus and Mars to the mass of the planet usually were not smaller than that with Earth. Among 30,000 considered objects with initial orbits close to those of JFCs, a few objects got Earth-crossing orbits with semimajor axesa<2 AU and aphelion distancesQ<4.2 AU, or even got inner-Earth (Q<0.983 AU), Aten, or typical asteroidal orbits, and moved in such orbits for more than 1 Myr (up to tens or even hundreds of Myr). From a dynamical point of view, the fraction of extinct comets among near-Earth objects can exceed several tens of percent, but, probably, many extinct comets disintegrated into mini-comets and dust during a smaller part of their dynamical lifetimes.
Is the near-Earth asteroid 2000 PG3 an extinct comet?
Authors: Babadzhanov Pulat B. , Williams Iwan P.
Published: May 2007

The existence of an observed meteor shower associated with some Near-Earth Asteroid (NEA) is one of the few useful criteria that can be used to indicate that such an object could be a candidate for being regarded as an extinct or dormant cometary nucleus. In order to identify possible new NEA-meteor showers associations, the secular variations of the orbital elements of the NEA 2000 PG3, with comet-like albedo (0.02), and moving on a comet-like orbit, was investigated under the gravitational action of the Sun and six planets (Mercury to Saturn) over one cycle of variation of the argument of perihelion. The theoretical geocentric radiants and velocities of four possible meteor showers associated with this object are determined. Using published data, the theoretically predicted showers were identified with the night-time September Northern and Southern δ-Piscids fireball showers and several fireballs, and with the day-time meteor associations γ-Arietids and α-Piscids. The character of the orbit and low albedo of 2000 PG3, and the existence of observed meteor showers associated with 2000 PG3 provide evidence supporting the conjecture that this object may be of cometary nature.
Inverse problems of NEO photometry: Imaging the NEO population
Authors: Kaasalainen1 Mikko , Ďurech Josef
Published: May 2007

The physical properties of NEOs and other asteroids are mostly obtained with photometry. The resulting models describe the shapes, spin states, scattering properties and surface structure of the targets, and are the solutions of inverse problems involving comprehensive mathematical analysis. We review what can and cannot be obtained from photometric (and complementary) data, and how all this is done in practice. The role of photometry will become completely dominating with the advent of large-scale surveys capable of producing calibrated brightness data. Due to their quickly changing geometries with respect to the Earth, NEOs are the population that can be mapped the fastest.
The Dynamics of NEO Binary Asteroids
Authors: Scheeres D.J.
Published: May 2007

The dynamics of binary Near-Earth objects (NEO) are discussed and a simple model for the study of their dynamics is introduced. Main results on the motion and stability of binary asteroids are reviewed. The effect of perturbations external to the binary system, including solar gravity, solar radiation pressure, and planetary gravity, are considered.
Tidal disturbances of small cohesionless bodies: limits on planetary close approach distances
Authors: Michel Patrick , Holsapple K. A.
Published: May 2007

The population of Near-Earth Objects contains small bodies that can make very close passages to the Earth and the other planets. Depending on the approach distance and the object's internal structure, some shape readjustment or disruption may occur as a result of tidal forces. A real example is the comet Shoemaker Levy 9 which disrupted into 21 fragments as a result of a close approach to Jupiter, before colliding with the planet during the next passage in July 1994. We have recently developed an exact analytical theory for the distortion and disruption limits of spinning ellipsoidal bodies subjected to tidal forces, using the Drucker-Prager strength model with zero cohesion. This model is the appropriate one for dry granular materials such as sands and rocks, for rubble-pile asteroids and comets, as well as for larger planetary satellites, asteroids and comets for which the cohesion can be ignored. Here, we recall the general concept of this theory for which details and major results are given in a recent publication. In particular, we focus on the definition of “material strength”: while it has great implications this concept is often misunderstood in the community of researchers working on small bodies. Then, we apply our theory to a few real objects, showing that it can provide some constraints on their unknown properties such as their bulk density. In particular it can be used to estimate the maximum bulk density that a particular object, such as 99942 Apophis, must have to undergo some tidal readjustments during a predicted planetary approach. The limits of this theory are also discussed. The cases where internal cohesion cannot be ignored will then be investigated in the near future.
Collision and impact simulations including porosity
Authors: Benz Willy , Jutzi Martin
Published: May 2007

The Smooth Particle Hydrodynamics (SPH) impact code (Benz & Asphaug 1994) has been developed for the simulation of impacts and collisions involving brittle solids in the strength-and gravity-dominated regime. In the latter regime, the gravitational overburden is used to increase the fracture threshold. In this paper, we extend our numerical approach to include the effect of porosity at a sub-resolution scale by adapting the so-called P -α model (Herrman 1969). Using our extended 3D SPH impact code, we investigated collisions between porous bodies to examine the sensitivity of collisional outcomes to the degree of porosity. Two applications that illustrate the capabilities of our approach are shown: 1) the modeling of a Deep Impact-like impact and 2) the computation of the amount of momentum transferred to an asteroid following the impact of a high velocity projectile.
Space weathering and tidal effects among near-Earth objects
Authors: Marchi S. , Paolicchi P. , Nesvorný D. , Magrin S. , Lazzarin M.
Published: May 2007

The effect of the space weathering on the spectral properties of the S–complex asteroids (both Main Belt bodies and near–Earth asteroids) has been widely discussed in recent times. It has also shown that the evolution of spectral properties of planet–crossing bodies, and in particular of near–Earth asteroids (NEAs), is also affected by other physical processes, such as tidal resurfacing due to close encounters with planetary bodies. In this paper we show how to combine previous analyses with the purpose of obtaining a global model for NEAs space weathering.
Near-Earth objects as principal impactors of the Earth: Physical properties and sources of origin
Authors: Lupishko Dimitrij F. , Martino Mario Di , Binzel Richard P.
Published: May 2007

Near-Earth objects (NEOs) are objects of a special interest from the point of view not only of cosmogonic problems of the Solar system, but of the applied problems as well (the problem of asteroid hazard, NEOs as the potential sources of raw materials, etc.). They are much smaller in sizes than main-belt asteroids (MBAs), very irregular in shape and covered with a great number of craters of different sizes. Most of NEOs are covered by regolith of low thermal inertia and different thickness. Objects with complex non-principal axis rotation (tumbling bodies) and with super-fast rotational periods have been detected among them. The new data, based on photometric and radar observations, evidence that about 15-20 %; of NEOs could be binary systems. Most of the classified NEOs fragments of differentiated assemblages of S-and Q-types. Analysis of physical properties of NEOs clearly indicates that the asteroid main-belt is the principal source of their origin and only about 10 % of NEOs have a cometary origin.
Near-Earth-Object identification over apparitions usingn-body ranging
Authors: Granvik Mikael , Muinonen Karri
Published: May 2007

Under ideal conditions, Earth-based telescopes can observe near-Earth objects (NEOs) continuously from a few days to months during each apparition. Due to the usually complicated dynamics of the Sun-Earth-NEO triplet, the time interval between consecutive apparitions typically ranges from months to several years. On these time scales, exiguous single-apparition sets (SASs) of observations having short observational time-intervals lead to substantial orbital uncertainties. Linking of SASs over apparitions thus becomes a nontrivial task. For example, of a total of roughly 4,100 NEO observation sets, or orbits, currently known, some 2,300 are SASs, for which the observational time interval is less than 180 days. Either these SASs have not been observed at an apparition following the discovery apparition or the linkage of SASs has failed, an option which should preferably be eliminated. As a continuation to our work on the short-arc linking problem at the discovery moment (Granvik & Muinonen, 2005,Icarus179, 109), we have investigated the possibility of using a similar method for linking exiguous SASs over apparitions. Assuming that the observational time-interval for SASs of NEOs is typically at least one day (minimum requirement set by the Minor Planet Center), the orbital-element probability-density function is constrained as compared to the typical short-arc case with an observational time interval of only a few tens of minutes. Because of the smaller orbital-element uncertainty, we can use the short-arc method (comparison in ephemeris space) for longer time spans, or even do the comparison directly in the orbital-element space (Cartesian, Keplerian, equinoctial, etc.), thus allowing us to assess the problem of linking SASs of NEOs. Due to possible close approaches with the Earth and other planets, and substantial propagation intervals, we have developed newn-body techniques for the orbit computation.
Low solar elongation searches for NEO: a deep sky test and its implications for survey strategies
Authors: Boattini Andrea , Milani A. , Gronchi G. F. , Spahr T. , Valsecchi G. B.
Published: May 2007

A survey for NEO aiming at 90% completeness for a given size range cannot ignore that a significant fraction of the population is observable essentially only at low solar elongation, in the so called “sweet spots” There are several penalties for such low elongation: poorer observing conditions imply a lower limiting magnitude, shorter available time in each night and a more difficult orbit determination. Our aim is to show that these difficulties can be overcome. We have tested the observation procedures and the mathematical methods of orbit determination on two sweet spot test runs. One was performed at ESO La Silla in Jan–Feb 2005, the other at Mauna Kea in Sept–Dec 2005. The results of the tests are presented in this paper; the observed area was not large enough (especially at Mauna Kea) to discover a significant number of new NEO, the purpose was rather to identify the problems. These tests have allowed us to identify all the key elements to be accounted for in the strategy for a successful sweet spot NEO survey. When very short arc observations from different nights have to be identified, a specific difficulty occurs at the sweet spots: the same set of observations from three nights can be fitted to two incompatible orbits, in most cases including one NEO and one MBA. This can lead to two different failures (false positive, false negative) in deciding whether a NEO has been discovered. The classical theory of preliminary orbits shows that three observations at an elongation less than 116.5° can be compatible with two different orbits. From this theory we have derived an algorithm to find the alternate solution, if it exists, when only one is available. In this way we have generated a set of examples of possible discoveries with two well determined but incompatible solutions. Most of the MBA-NEO alternatives have been solved by finding a known MBA which could be identified; in two cases the MBA solution has been confirmed by a later observation.
Spacewatch preparations for the era of deep all-sky surveys
Authors: McMillan Robert S. ,   The Spacewatch Team
Published: May 2007

The Spacewatch Project at the University of Arizona uses a 0.9-meter and a 1.8-meter telescope to search for new Near-Earth Objects (NEOs) and make astrometric followup measurements of known ones. Among the presently operational asteroid astrometry programs, Spacewatch is uniquely suited to support discoveries by the planned deep all-sky surveys. The Spacewatch 1.8-meter telescope is the largest in the world that is used exclusively for observations of asteroids and comets. Since 2003 January 1, Spacewatch has made ~2400 separate-night detections (discoveries plus followup) of NEOs with absolute magnitude H≤ 22, including 117 fresh discoveries of NEOs with H≤22 and ~900 separate-night detections of Potentially Hazardous Asteroids (PHAs). Objects have been recovered at V=23 and at elongations less than 60 degrees from the Sun. Spacewatch followup observations have contributed to the removal of 137 objects from JPL's impact risk website. Examples of notable recoveries by Spacewatch include the extension of orbital arcs from one month to multi-opposition orbits, and a successful targeted search for a large PHA (1990 SM) with 80 degrees of uncertainty. Spacewatch has been making as many observations of PHAs with H≤22 and V>21 as all other followup stations combined. Followup of NEOs while they are not near Earth provides better leverage on orbital elements and will be well suited to follow up some of the discoveries by the larger-scale, deeper sky surveys: both ground- and space-based. Spacewatch is collaborating with the Panoramic Survey Telescope and Rapid Response System (PS) of the University of Hawaii's Institute for Astronomy. Each lunation, Spacewatch sends its listings of point sources detected in survey images for PS's moving object detection team to test their software. Spacewatch is also prepared to follow up objects of special interest, fast motion, or less than three nights of observations by PS itself. Spacewatch's current equipment is only a few years old, but there is still room to improve limiting magnitude & time efficiency.