Ben-Gera H.,Hebrew University
Plant signaling & behavior | Year: 2012
Elaboration of a complex leaves depends on the morphogenetic activity of a specific tissue at the leaf margin termed marginal-blastozon (MB). In tomato (Solanum lycopersicym), prolonged activity of the MB leads to the development of compound leaves. The activity of the MB is restricted by the TCP transcription factor LANCEOLATE (LA). Plants harboring the dominant LA mutant allele La-2 have simple leaves with a uniform blade. Conversely, leaves of pFIL > > miR319 are compound and grow indeterminately in their margins due to leaf overexpression of miR319, a negative regulator of LA and additional miR319-sensitive genes. We have recently shown that the auxin-response sensor DR5::VENUS marks and precedes leaflet initiation events in the MB. Mutations in ENTIRE (E), an auxin signal inhibitor from the Aux/IAA family, lead to the expansion of the DR5::VENUS signal to throughout the leaf-primordia margin, and to a simplified leaf phenotype. Here, we examined the interaction between auxin, E, and LA in tomato leaf development. In La-2 leaf primordia, the auxin signal is very weak and is diffused to throughout the leaf margin, suggesting that auxin acts within the developmental-context of MB activity, which is controlled by LA. e La-2 double mutants showed an enhanced simple leaf phenotype and e pFIL > > miR319 leaves initiated less leaflets than wild-type, but their margins showed continuous growth. These results suggest that E and auxin affect leaflet initiation within the context of the extended MB activity, but their influence on the extent of indeterminate growth of the leaf is minor.
Baneth G.,Hebrew University
International Journal for Parasitology | Year: 2014
A wide variety of pathogens is transmitted from ticks to vertebrates including viruses, bacteria, protozoa and helminths, of which most have a life cycle that requires passage through the vertebrate host. Tick-borne infections of humans, farm and companion animals are essentially associated with wildlife animal reservoirs. While some flying insect-borne diseases of humans such as malaria, filariasis and Kala Azar caused by Leishmania donovani target people as their main host, major tick-borne infections of humans, although potentially causing disease in large numbers of individuals, are typically an infringement of a circulation between wildlife animal reservoirs and tick vectors. While new tick-borne infectious agents are frequently recognised, emerging agents of human tick-borne infections were probably circulating among wildlife animal and tick populations long before being recognised as clinical causes of human disease as has been shown for Borrelia burgdorferi sensu lato. Co-infection with more than one tick-borne infection is common and can enhance pathogenic processes and augment disease severity as found in B. burgdorferi and Anaplasma phagocytophilum co-infection. The role of wild animal reservoirs in co-infection of human hosts appears to be central, further linking human and animal tick-borne infections. Although transmission of most tick-borne infections is through the tick saliva, additional routes of transmission, shown mostly in animals, include infection by oral uptake of infected ticks, by carnivorism, animal bites and transplacentally. Additionally, artificial infection via blood transfusion is a growing threat in both human and veterinary medicine. Due to the close association between human and animal tick-borne infections, control programs for these diseases require integration of data from veterinary and human reporting systems, surveillance in wildlife and tick populations, and combined teams of experts from several scientific disciplines such as entomology, epidemiology, medicine, public health and veterinary medicine. © 2014 Australian Society for Parasitology Inc.
Kopf J.,Microsoft |
Lischinski D.,Hebrew University
ACM Transactions on Graphics | Year: 2011
We describe a novel algorithm for extracting a resolutionindependent vector representation from pixel art images, which enables magnifying the results by an arbitrary amount without image degradation. Our algorithm resolves pixel-scale features in the input and converts them into regions with smoothly varying shading that are crisply separated by piecewise-smooth contour curves. In the original image, pixels are represented on a square pixel lattice, where diagonal neighbors are only connected through a single point. This causes thin features to become visually disconnected under magnification by conventional means, and creates ambiguities in the connectedness and separation of diagonal neighbors. The key to our algorithm is in resolving these ambiguities. This enables us to reshape the pixel cells so that neighboring pixels belonging to the same feature are connected through edges, thereby preserving the feature connectivity under magnification. We reduce pixel aliasing artifacts and improve smoothness by fitting spline curves to contours in the image and optimizing their control points. © 2011 ACM.
Berman A.,Hebrew University
Journal of Dairy Science | Year: 2011
Environmental heat stress, present during warm seasons and warm episodes, severely impairs dairy cattle performance, particularly in warmer climates. It is widely viewed that warm climate breeds (Zebu and Sanga cattle) are adapted to the climate in which they evolved. Such adaptations might be exploited for increasing cattle productivity in warm climates and decrease the effect of warm periods in cooler climates. The literature was reviewed for presence of such adaptations. Evidence is clear for resistance to ticks and tick-transmitted diseases in Zebu and Sanga breeds as well as for a possible development of resistance to ticks in additional breeds. Development of resistance to ticks demands time; hence, it needs to be balanced with potential use of insecticides or vaccination. The presumption of higher sweating rates in Zebu-derived breeds, based upon morphological differences in sweat glands between breeds, has not been substantiated. Relatively few studies have examined hair coat characteristics and their responses to seasonal heat, particularly in temperate climate breeds. Recently, a gene for slick hair coat has been observed that improved heat tolerance when introduced into temperate climate breeds. No solid evidence exists that hair coat in these lines is lighter than in well-fed warm climate-adapted Holsteins. Warm climate breeds and their F1 crosses share as dominant characteristics lower maintenance requirements and milk yields, and limited response to improved feeding and management. These characteristics are not adaptations to a feed-limited environment but are constitutive and useful in serving survival when feed is scarce and seasonal and high temperatures prevail. The negative relationship between milk yield and fertility present in temperate climates breeds also prevails in Zebu cattle. Fertility impairment by warm conditions might be counteracted in advanced farming systems by extra corporeal early embryo culture. In general, adaptations found in warm climate cattle breeds did not increase heat dissipation capacity, but rather diminished climate-induced strain by decreasing milk production. The negative relationship between reproductive efficiency and milk yield, although relatively low, also appears in Zebu cattle. This association, coupled with limited feed intake, acting over millennia, probably created the selection pressure for a low milk production in these breeds. © 2011 American Dairy Science Association.
Telep C.W.,George Mason University |
Weisburd D.,Hebrew University
Justice Quarterly | Year: 2014
Hot spots policing has been shown to be an effective strategy for reducing crime across a number of rigorous evaluations, but despite this strong body of research, there still exist gaps in our knowledge of how officers can best respond to hot spots. We report on a randomized experiment in Sacramento, California that begins to address these gaps by testing the recommendation from prior research that police officers randomly rotate between hot spots, spending about 15 min patrolling in each. Our results suggest significant overall declines in both calls for service and crime incidents in the treatment hot spots relative to the controls. Additionally, the study was carried out primarily by the Sacramento Police Department without any outside funding. In an era of limited economic resources for policing, this experiment suggests a model by which police agencies can take ownership of science and oversee the implementation and evaluation of evidence-based interventions. © 2012 Academy of Criminal Justice Sciences.