Tied factor analysis for face recognition across large pose differences

Face recognition algorithms perform very unreliably when the pose of the probe face is different from the gallery face: typical feature vectors vary more with pose than with identity. We propose a generative model that creates a one-to-many mapping from an idealized “identity” space to the observed data space. In identity space, the representation for each individual does not vary with pose. We model the measured feature vector as being generated by a pose-contingent linear transformation of the identity variable in the presence of Gaussian noise. We term this model “tied” factor analysis. The choice of linear transformation (factors) depends on the pose, but the loadings are constant (tied) for a given individual. We use the EM algorithm to estimate the linear transformations and the noise parameters from training data. We propose a probabilistic distance metric that allows a full posterior over possible matches to be established. We introduce a novel feature extraction process and investigate recognition performance by using the FERET, XM2VTS, and PIE databases. Recognition performance compares favorably with contemporary approaches

Evaluation of cost-effective strategies for rabies post-exposure vaccination in low-income countries

<b>Background:</b> Prompt post-exposure prophylaxis (PEP) is essential in preventing the fatal onset of disease in persons exposed to rabies. Unfortunately, life-saving rabies vaccines and biologicals are often neither accessible nor affordable, particularly to the poorest sectors of society who are most at risk and upon whom the largest burden of rabies falls. Increasing accessibility, reducing costs and preventing delays in delivery of PEP should therefore be prioritized.<p></p> <b>Methodology/Principal Findings:</b> We analyzed different PEP vaccination regimens and evaluated their relative costs and benefits to bite victims and healthcare providers. We found PEP vaccination to be an extremely cost-effective intervention (from $200 to less than$60/death averted). Switching from intramuscular (IM) administration of PEP to equally efficacious intradermal (ID) regimens was shown to result in significant savings in the volume of vaccine required to treat the same number of patients, which could mitigate vaccine shortages, and would dramatically reduce the costs of implementing PEP. We present financing mechanisms that would make PEP more affordable and accessible, could help subsidize the cost for those most in need, and could even support new and existing rabies control and prevention programs.<p></p> <b>Conclusions/Significance:</b> We conclude that a universal switch to ID delivery would improve the affordability and accessibility of PEP for bite victims, leading to a likely reduction in human rabies deaths, as well as being economical for healthcare providers.<p></p&gt

Admission Diagnosis of Cerebral Malaria in Adults in an Endemic Area of Tanzania:Implications and Clinical Description

Cerebralmalariais commonly diagnosed in adults in endemic areas in Africa, both in hospitals and in the community. This presents a paradox inconsistent with the epidemiological understanding that the development of immunity during childhood confers protection against severe disease in adult life. To establish the contribution of Plasmodium falciparum infection in adults admitted with neurological dysfunction in an endemic area, to assess the implications of an admission clinical diagnosis of ‘cerebral malaria’ on the treatment and clinical outcome, and to describe the clinical features of patients with malaria parasitaemia. Prospective observational study. We studied adult patients admitted with neurological dysfunction to Muhimbili National Hospital, Dar-es-Salaam, Tanzania from October 2000 to July 2001. A full blood count was done and serum creatinine, blood glucose and P. falciparum parasite load were measured. Of 199 patients (median age 34.5 years), 38% were diagnosed as ‘cerebral malaria’ on admission, but only 7.5% had detectable parasitaemia, giving a positive predictive value of 13.3%. Only 1% fulfilled the WHO criteria for cerebral malaria. The prevalence of parasitaemia (7.5%) was less than that observed in a group of asymptomatic controls (9.3%), but distribution of parasite densities was higher in the patients. Mortality was higher in patients with no parasitaemia (22.3%) than in those with parasitaemia (13%). Cerebral malaria was grossly overdiagnosed, resulting in unnecessary treatment and insufficient investigation of other possible diagnoses, which could lead to higher mortality. Extension of this misperception to the assessment of cause of death in community surveys may lead to an overestimation of the impact of malaria in adults.\u

Survival of thermophilic spore-forming bacteria in a 90+ year old milk powder from Ernest Shackelton's Cape Royds Hut in Antarctica

Milk powder taken to Antarctica on Shackelton's British Antarctic Expedition in 1907 was produced in New Zealand by a roller drying process in the first factory in the world dedicated to this process. Thermophilic bacilli are the dominant contaminants of modern spray-dried milk powders and the 1907 milk powder allows a comparison to be made of contaminating strains in roller-dried and spray-dried powders. Samples of milk powder obtained from Shackelton's Hut at Cape Royds had low levels of thermophilic contamination (<500 cfu ml−1) but the two dominant strains (Bacillus licheniformis strain F and Bacillus subtilis) were typical of those found in spray-dried powders. Soil samples from the floor of the hut also contained these strains, whereas soils distant from the hut did not. Differences in the RAPD profiles of isolates from the milk powder and the soils suggest that contamination of the milk from the soil was unlikely. It is significant that the most commonly encountered contaminant strain in modern spray-dried milk (Anoxybacillus flavithermus strain C) was not detected in the 1907 sample

DETAILED GEOLOGIC STUDIES OF PALEOSEISMIC FEATURES EXPOSED AT SITES IN THE EAST TENNESSEE SEISMIC ZONE: EVIDENCE FOR LARGE, PREHISTORIC EARTHQUAKES

The East Tennessee seismic zone (ETSZ) is the second most active in the eastern United States, but recorded earthquakes do not exceed Mw [moment magnitude] = 4.6. Earthquake epicenters are located 5-26 kilometers deep in autochthonous basement, and faults producing these earthquakes do not break the surface. Detailed paleoseismic investigations at sites within the ETSZ include: detailed geological mapping, trenching, aerial photograph reconnaissance, X-ray diffraction (XRD), grain-size analysis, and optically stimulated luminescence dating of alluvium. Site DL-6 near Dandridge, Tennessee, reveals a complex array of features providing evidence that at least 4‒6 Mw \u3e 6 earthquakes affected the area. A thrust fault with ~1 meter displacement is traceable for ~50 meters in the mapped area from Quaternary terrace sediments into Ordovician Sevier Shale saprolite where it develops multiple splays. This fault truncates a 30 centimeter-wide Quaternary sediment-filled fissure; the fissure is also offset ~10 centimeters by a small strike-slip fault that truncates against a splay of the main thrust fault. The fissure may be traceable for over 2 kilometers across Douglas Reservoir. Fault surface and slickenline orientations indicate west-vergent slip on many thrust splay surfaces. Fracture orientations measured at site DL-6 are close to those in Sevier Shale here; reactivation of near-vertical fractures is mostly strike-slip. Additionally, shale chips in Quaternary sediment at a nearby site at Dandridge, Tennessee, contain the same mineralogy as underlying Sevier Shale, indicating that these chips may have been liquefied and brought up through Quaternary terrace sediments during an earthquake. Sites along the Chattooga River near Lyerly, Georgia, provide evidence for at least one Mw \u3e 6 earthquake. Sand dikes emanating from a source bed in a cut bank contain liquefiable sediments that intruded overlying cap sediments; grain-size and XRD analyses suggest cap sediments are more clay-rich than source or dike sediments. Aerial photographs of the area contain elliptical discontinuities that may represent sand blow deposits. Field reconnaissance of the area identified possible feeder dikes to sand blows; further investigation is required. Collectively, these data provide substantial evidence for the occurrence of Mw \u3e 6 earthquakes in the ETSZ, and motivate further paleoseismic studies here