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B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Engineering Faculty Profile Andrzej Nowak Professor Elton and Lois G Huff Eminent Scholar Chair Structural Department Chair Civil Engineering 238 Harbert Center asn0007auburnedu 3348446216 CV Education PhD Civil Engineering Warsaw University of Technology MS Civil Engineering Warsaw University of Technology BS Civil Engineering Warsaw University of Technology Research Interests Reliability of Structures Design Code Calibration Bridge Engineering Load Models Field Testing Procedures KeywordsTags Reliability of Structures Risk Analysis Reliability Index LRFD Code Calibration Bridge Engineering Bridge Loads Field Testing WeighinMotion Measurements

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O B I I O O O O O O O O O O O O O O O

andrzej nowak
professor
reliability of structures


Home Networking LAN switching firststep Layer 2 Switching Methods LAN switches are characterized by the forwarding method that they support such as a storeandforward switch cutthrough switch or fragmentfree switch In the storeandforward switching method error checking is performed against the frame and any frame with errors is discarded With the cutthrough switching method no error checking is performed against the frame which makes forwarding the frame through the switch faster than storeandforward switches StoreandForward Switching Storeandforward switching means that the LAN switch copies each complete frame into the switch memory buffers and computes a cyclic redundancy check CRC for errors CRC is an errorchecking method that uses a mathematical formula based on the number of bits 1s in the frame to determine whether the received frame is errored If a CRC error is found the frame is discarded If the frame is error free the switch forwards the frame out the appropriate interface port as illustrated in Figure 67 Figure 67 StoreandForward Switch Discarding a Frame with a Bad CRC View full size image An Ethernet frame is discarded if it is smaller than 64 bytes in length a runt or if the frame is larger than 1518 bytes in length a giant as illustrated in Figure 68 Figure 68 Runts and Giants in the Switch View full size image note Some switches can be configured to carry giant or jumbo frames If the frame does not contain any errors and is not a runt or a giant the LAN switch looks up the destination address in its forwarding or switching table and determines the outgoing interface It then forwards the frame toward its intended destination StoreandForward Switching Operation Storeandforward switches store the entire frame in internal memory and check the frame for errors before forwarding the frame to its destination Storeandforward switch operation ensures a high level of errorfree network traffic because bad data frames are discarded rather than forwarded across the network as illustrated in Figure 69 Figure 69 StoreandForward Switch Examining Each Frame for Errors Before Forwarding to Destination Network Segment View full size image The storeandforward switch shown in Figure 69 inspects each received frame for errors before forwarding it on to the frames destination network segment If a frame fails this inspection the switch drops the frame from its buffers and the frame is thrown in to the proverbial bit bucket A drawback to the storeandforward switching method is one of performance because the switch has to store the entire data frame before checking for errors and forwarding This error checking results in high switch latency delay If multiple switches are connected with the data being checked at each switch point total network performance can suffer as a result Another drawback to storeandforward switching is that the switch requires more memory and processor central processing unit CPU cycles to perform the detailed inspection of each frame than that of cutthrough or fragmentfree switching CutThrough Switching With cutthrough switching the LAN switch copies into its memory only the destination MAC address which is located in the first 6 bytes of the frame following the preamble The switch looks up the destination MAC address in its switching table determines the outgoing interface port and forwards the frame on to its destination through the designated switch port A cutthrough switch reduces delay because the switch begins to forward the frame as soon as it reads the destination MAC address and determines the outgoing switch port as illustrated in Figure 610 Figure 610 CutThrough Switch Examining Each Frame Header Before Forwarding to Destination Network Segment View full size image The cutthrough switch shown in Figure 610 inspects each received frames header to determine the destination before forwarding on to the frames destination network segment Frames with and without errors are forwarded in cutthrough switching operations leaving the error detection of the frame to the intended recipient If the receiving switch determines the frame is errored the frame is thrown out to the bit bucket where the frame is subsequently discarded from the network Cutthrough switching was developed to reduce the delay in the switch processing frames as they arrive at the switch and are forwarded on to the destination switch port The switch pulls the frame header into its port buffer When the destination MAC address is determined by the switch the switch forwards the frame out the correct interface port to the frames intended destination Cutthrough switching reduces latency inside the switch If the frame was corrupted in transit however the switch still forwards the bad frame The destination receives this bad frame checks the frames CRC and discards it forcing the source to resend the frame This process wastes bandwidth and if it occurs too often network users experience a significant slowdown on the network In contrast storeandforward switching prevents errored frames from being forwarded across the network and provides for quality of service QoS managing network traffic flow note Todays switches dont suffer the network latency that older legacy switches labored under This minimizes the effect switch latency has on your traffic Todays switches are better suited for a storeandforward environment CutThrough Switching Operation Cutthrough switches do not perform any error checking of the frame because the switch looks only for the frames destination MAC address and forwards the frame out the appropriate switch port Cutthrough switching results in low switch latency The drawback however is that bad data frames as well as good frames are sent to their destinations At first blush this might not sound bad because most network cards do their own frame checking by default to ensure good data is received You might find that if your network is broken down into workgroups the likelihood of bad frames or collisions FragmentFree Switching Fragmentfree switching is also known as runtless switching and is a hybrid of cutthrough and storeandforward switching Fragmentfree switching was developed to solve the latecollision problem note Recall that when two systems transmissions occur at the same time the result is a collision Collisions are a part of Ethernet communications and do not imply any error condition A late collision is similar to an Ethernet collision except that it occurs after all hosts on the network should have been able to notice that a host was already transmitting A late collision indicates that another system attempted to transmit after a host has transmitted at least the first 60 bytes of its frame Late collisions are often caused by an Ethernet LAN being too large and therefore needing to be segmented Late collisions can also be caused by faulty network devices on the segment and duplex for example halfduplexfullduplex mismatches between connected devices FragmentFree Switching Operation Fragmentfree switching works like cutthrough switching with the exception that a switch in fragmentfree mode stores the first 64 bytes of the frame before forwarding Fragmentfree switching can be viewed as a compromise between storeandforward switching and cutthrough switching The reason fragmentfree switching stores only the first 64 bytes of the frame is that most network errors and collisions occur during the first 64 bytes of a frame note Different methods work better at different points in the network For example cutthrough switching is best for the network core where errors are fewer and speed is of utmost importance Storeandforward is best at the network access layer where most network problems and users are located Layer 3 Switching Layer 3 switching is another example of fragmentfree switching Up to now this discussion has concentrated on switching and bridging at the data link layer Layer 2 of the Open System Interconnection OSI model When bridge technology was first developed it was not practical to build wirespeed bridges with large numbers of highspeed ports because of the manufacturing cost involved With improved technology many functions previously implemented in software were moved into the hardware increasing performance and enabling manufacturers to build reasonably priced wirespeed switches Whereas bridges and switches work at the data link layer OSI Layer 2 routers work at the network layer OSI Layer 3 Routers provide functionality beyond that offered by bridges or switches As a result however routers entail greater complexity Like early bridges routers were often implemented in software running on a specialpurpose processing platform such as a personal computer PC with two network interface cards NICs and software to route data between each NIC as illustrated in Figure 611 Figure 611 PC Routing with Two NICs View full size image The early days of routing involved a computer and two NIC cards not unlike two people having a conversation but having to go through a third person to do so The workstation would send its traffic across the wire and the routing computer would receive it on one NIC determine that the traffic would have to be sent out the other NIC and then resend the traffic out this other NIC note In the same way that a Layer 2 switch is another name for a bridge a Layer 3 switch is another name for a router This is not to say that a Layer 3 switch and a router operate the same way Layer 3 switches make decisions based on the portlevel Internet Protocol IP addresses whereas routers make decisions based on a map of the Layer 3 network maintained in a routing table Multilayer switching is a switching technique that switches at both the data link OSI Layer 2 and network OSI Layer 3 layers To enable multilayer switching LAN switches must use storeandforward techniques because the switch must receive the entire frame before it performs any protocol layer operations as illustrated in Figure 612 Figure 612 Layer 3 Multilayer Switch Examining Each Frame for Error Before Determining the Destination Network Segment Based on the Network Address View full size image Similar to a storeandforward switch with multilayer switching the switch pulls the entire received frame into its memory and calculates its CRC It then determines whether the frame is good or bad If the CRC calculated on the packet matches the CRC calculated by the switch the destination address is read and the frame is forwarded out the correct switch port If the CRC does not match the frame the frame is discarded Because this type of switching waits for the entire frame to be received before forwarding port latency times can become high which can result in some latency Layer 3 Switching Operation You might be asking yourself Whats the difference between a Layer 3 switch and a router The fundamental difference between a Layer 3 switch and a router is that Layer 3 switches have optimized hardware passing data traffic as fast as Layer 2 switches However Layer 3 switches make decisions regarding how to transmit traffic at Layer 3 just as a router does note Within the LAN environment a Layer 3 switch is usually faster than a router because it is built on switching hardware Bear in mind that the Layer 3 switch is not as versatile as a router so do not discount the use of a router in your LAN without first examining your LAN requirements such as the use of network address translation NAT Before going forward with this discussion recall the following points A switch is a Layer 2 data link device with physical ports and that the switch communicates via frames that are placed on to the wire at Layer 1 physical A router is a Layer 3 network device that communicates with other routers with the use of packets which in turn are encapsulated inside frames Routers have interfaces for connection into the network medium For a router to route data over the Ethernet for instance the router requires an Ethernet interface as illustrated in Figure 613 Figure 613 Router Interfaces A serial interface is required for the router connecting to a widearea network WAN and a Token Ring interface is required for the router connecting to a Token Ring network A simple network made up of two network segments and an internetworking device in this case a router is shown in Figure 614 Figure 614 TwoSegment Network with a Layer 3 Router The router in Figure 614 has two Ethernet interfaces labeled E0 and E1 The primary function of the router is determining the best network path in a complex network A router has three ways to learn about networks and make the determination regarding the best path through locally connected ports static route entries and dynamic routing protocols The router uses this learned information to make a determination by using routing protocols Some of the more common routing protocols used include Routing Information Protocol RIP Open Shortest Path First OSPF Interior Gateway Routing Protocol IGRP and Border Gateway Protocol BGP note Routing protocols are used by routers to share information about the network Routers receive and use the routing protocol information from other routers to learn about the state of the network Routers can modify information received from one router by adding their own information along with the original information and then forward that on to other routers In this way each router can share its version of the network Packet Switching Layer 3 information is carried through the network in packets and the transport method of carrying these packets is called packet switching as illustrated in Figure 615 Figure 615 Packet Switching Between Ethernet and Token Ring Network Segments Figure 615 shows how a packet is delivered across multiple networks Host A is on an Ethernet segment and Host B on a Token Ring segment Host A places an Ethernet frame encapsulating an Internet Protocol IP packet on to the wire for transmission across the network The Ethernet frame contains a source data link layer MAC address and a destination data link layer MAC address The IP packet within the frame contains a source network layer IP address TCPIP network layer address and a destination network layer IP address The router maintains a routing table of network paths it has learned and the router examines the network layer destination IP address of the packet When the router has determined the destination network from the destination IP address the router examines the routing table and determines whether a path exists to that network In the case illustrated in Figure 615 Host B is on a Token Ring network segment directly connected to the router The router peels off the Layer 2 Ethernet encapsulation forwards the Layer 3 data packet and then reencapsulates the packet inside a new Token Ring frame The router sends this frame out its Token Ring interface on to the segment where Host B will see a Token Ring frame containing its MAC address and process it Note the original frame was Ethernet and the final frame is Token Ring encapsulating an IP packet This is called media transition and is one of the features of a network router When the packet arrives on one interface and is forwarded to another it is called Layer 3 switching or routing Routing Table Lookup Routers and Layer 3 switches perform table lookups determining the next hop next router or Layer 3 switch along the route which in turn determines the output port over which to forward the packet or frame The router or Layer 3 switch makes this decision based on the network portion of the destination address in the received packet This lookup results in one of three actions The destination network is not reachable There is no path to the destination network and no default network In this case the packet is discarded The destination network is reachable by forwarding the packet to another router There is a match of the destination network against a known table entry or to a default route if a method for reaching the destination network is unknown The first lookup tells the next hop Then a second lookup is performed to determine how to get to the next hop Then a final determination of the exit port is reached The first lookup can return multiple paths so the port is not known until after the determination of how to get there is made In either case the lookup returns the network Layer 3 address of the nexthop router and The destination network is known to be directly attached to the router The port is directly attached to the network and reachable For directly attached networks the next step maps the host portion of the destination network address to the data link MAC address for the next hop or end node using the ARP table for IP It does not map the destination network address to the router interface It needs to use the MAC of the final end node so that the node picks up the frame from the medium Also you are assuming IP when stating that the router uses the ARP table Other Layer 3 protocols such as Internetwork Packet Exchange IPX do not use ARP to map their addresses to MAC addresses Routing table lookup in an IP router might be considered more complex than a MAC address lookup for a bridge because at the data link layer addresses are 48bits in length with fixedlength fieldsthe OUI and ID Additionally datalink address space is flat meaning there is no hierarchy or dividing of addresses into smaller and distinct segments MAC address lookup in a bridge entails searching for an exact match on a fixedlength field whereas address lookup in a router looks for variablelength fields identifying the destination network IP addresses are 32 bits in length and are made up of two fields the network identifier and the host identifier as illustrated in Figure 616 Figure 616 IP Address Space Both the network and host portions of the IP address can be of a variable or fixed length depending on the hierarchical network address scheme used Discussion of this hierarchical or subnetting scheme is beyond the scope of this book but suffice to say you are concerned with the fact that each IP address has a network and host identifier The routing table lookup in an IP router determines the next hop by examining the network portion of the IP address After it determines the best match for the next hop the router looks up the interface port to forward the packets across as illustrated in Figure 617 Figure 617 Routing Table Lookup Operation View full size image Figure 617 shows that the router receives the traffic from Serial Port 1 S1 and performs a routing table lookup determining from which port to forward out the traffic Traffic destined for Network 1 is forwarded out the Ethernet 0 E0 port Traffic destined for Network 2 is forwarded out the Token Ring 0 T0 port and traffic destined for Network 3 is forwarded out Serial Port 0 S0 note In terms of the Cisco Internet Operating System IOS interface port numbers begin with zero 0 such as serial port 0 S0 Not all vendors including Cisco use ports some use slots or modules which might begin with zero or one The host identifier portion of the network address is examined only if the network lookup indicates that the destination is on a locally attached network Unlike datalink addresses the dividing line between the network identifier and the host identifier is not in a fixed position throughout the network Routing table entries can exist for network identifiers of various lengths from 0 bits in length specifying a default route to 32 bits in length for hostspecific routes According to IP routing procedures the lookup result returned should be the one corresponding to the entry that matches the maximum number of bits For example a network host might have both the IP address of 6898134209 and a MAC address of 000c415340d3 The router makes decisions based on the IP address 6898134209 whereas the switch makes decisions based on the MAC address 000c415340d3 Both addresses identify the same host on the network but are used by different network devices when forwarding traffic to this host ARP Mapping Address Resolution Protocol ARP is a network layer protocol used in IP to convert IP addresses into MAC addresses A network device looking to learn a MAC address broadcasts an ARP request onto the network The host on the network that has the IP address in the request replies with its MAC hardware address This is called ARP mapping the mapping of a Layer 3 network address to a Layer 2 data link address note Some Layer 3 addresses use the MAC address as part of their addressing scheme such as IPX Because the network layer address structure in IP does not provide for a simple mapping to datalink addresses IP addresses use 32 bits and datalink addresses use 48 bits It is not possible to determine the 48bit datalink address for a host from the host portion of the IP address For packets destined for a host not on a locally attached network the router performs a lookup for the nexthop routers MAC address For packets destined for hosts on a locally attached network the router performs a second lookup operation to find the destination address to use in the datalink Figure 618 Router ARP Cache Lookup View full size image After determining for which directly attached network the packet is destined the router looks up the destination MAC address in its ARP cache Recall that ARP enables the router to determine the corresponding MAC address when it knows the network IP address The router then forwards the packet across the local network in a frame with the MAC address of the local host or nexthop router note Note in Figure 618 that Net 3 Host 31 is not part of the ARP cache because during the routing table lookup the router determined that this packet is to be forwarded to another remote nonlocally attached network The result of this final lookup falls into one of the three following categories The packet is destined for the router itself The IP destination address network and station portion combined corresponds to one of the IP addresses of the router In this case the packet must be passed to the appropriate higherlayer entity within the router and not forwarded to any external port The packet is destined for a known host on the directly attached network This is the most common situation encountered by a network router The router determines the mapping from the ARP table and forwards the packet out the appropriate interface port to the local network The ARP mapping for the specified host is unknown The router initiates a discovery procedure by sending an ARP request determining the mapping of network to hardware address Because this discovery procedure takes time albeit measured in milliseconds the router might drop the packet that resulted in the discovery procedure in the first place Under steadystate conditions the router already has ARP mappings available for all communicating hosts The address discovery procedure is necessary when a previously unheardfrom host establishes a new communication session note The current version of Cisco IOS 120 Software drops the first packet for a destination without an ARP entry The IOS does this to handle denial of service DoS attacks against incomplete ARPs In other words it drops the frame immediately instead of awaiting a reply Fragmentation Each output port on a network device has an associated maximum transmission unit MTU Recall from earlier in this chapter that the MTU indicates the largest frame size measured in bytes that can be carried on the interface The MTU is often a function of the networking technology in use such as Ethernet Token Ring or PointtoPoint Protocol PPP PPP is used with Internet connections If the frame being forwarded is larger than the available space as indicated by the MTU the frame is fragmented into smaller pieces for transmission on the particular network Bridges can not fragment frames when forwarding between LANs of differing MTU sizes because datalink connections rarely have a mechanism for fragment reassembly at the receiver The mechanism is at the network layer implementation such as with IP which is capable of overcoming this limitation Network layer packets can be broken down into smaller pieces if necessary so that these packets can travel across a link with a smaller MTU Fragmentation is similar to taking a picture and cutting it into pieces so that each piece will fit into differently sized envelopes for mailing It is up to the sender to determine the size of the largest piece that can be sent and it is up to the receiver to reassemble these pieces Fragmentation is a mixed blessing although it provides the means of communication across different link technologies the processing accomplishing the fragmentation is significant and could be a burden on each device having to fragment and reassemble the data Further pieces for reassembly can be received out of As a rule it is best to avoid fragmentation in your network if at all possible It is more efficient for the sending station to send packets not requiring fragmentation anywhere along the path to the destination instead of sending large packets requiring intermediate routers to perform fragmentation note Hosts and routers can learn the maximum MTU available along a network path through the use of MTU discovery MTU discovery is a process by which each device in a network path learns the MTU size that the network path can support

O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Sibilisan Viridian Pigment This item can be used in tradeskills WT 08 Size TINY Class ALL Race ALL Item Lore Item Lore Item Type Misc Stackable 1000 Merchant Value 10 pp 0 gp 0 sp 0 cp Lucy Entry By SwiftyMUSE Live IC Last Updated 20181213 012238 Page Updated Fri Jan 12th 2018 Item Average Price No Data Pricing Data Rarity Common Level to Attain NA Drops Recipes Comments Drops This item is found on creatures Chardok EoK a chokidai fleshripper Frontier Mountains EoK a frontier bear a grove guardian Ancient Starcollector Guardian of the Pack Gates of KorSha a chokidai elder Howling Stones RoS Arisen Fenistra Arisen Mentor Sishallan Lceanium a drolvarg gnasher a greater plaguebone a petrifier cockatrice a plaguebone skeleton The Dreadland Wanderer The Lost Hunter Scorched Woods a cinder elemental a wurmscorched skeleton Plaguebringer Skyfire Mountains RoS a bottomless feaster Temple of Droga EoK mudman dredger The Overthere RoS a stoneglint cockatrice Used in 4 recipes Recipe list Premium only Zones Found In Chardok EoK Frontier Mountains EoK Gates of KorSha Howling Stones RoS Lceanium Scorched Woods Skyfire Mountains RoS Temple of Droga EoK The Overthere RoS Uploaded May 5th 2017 by iinelder Send a correction uses Dec 28 2016 at 828 AM Rating Good Shuraz Sage 962 posts These can be used to color the Lcea Katta ornaments They will become Praetor Denik ornaments a full suit of plate requires 14 of the pigments with no failures since its a 350 trivial and then a 450 trivial combine you might want to have a few extras around Took me 17 pigments to make my suit a full suit of cloth also takes 14 except an extra 9 for just a robe At least on fails the ornament is returned though you can lose the pigment part I lost several on a robe fail Total pigments used 32 The cost for the subcombine with the pigment is 2643 plat each It gets expensive Edited Dec 28th 2016 943am by Shuraz Edited Dec 28th 2016 944am by Shuraz Page top uses Dec 29 2016 at 559 PM Rating Excellent Gidono 5113 posts Shuraz wrote These can be used to color the Lcea Katta ornaments They will become Praetor Denik ornaments a full suit of plate requires 14 of the pigments with no failures since its a 350 trivial and then a 450 trivial combine you might want to have a few extras around Took me 17 pigments to make my suit a full suit of cloth also takes 14 except an extra 9 for just a robe At least on fails the ornament is returned though you can lose the pigment part I lost several on a robe fail Total pigments used 32 The cost for the subcombine with the pigment is 2643 plat each It gets expensive Edited Dec 28th 2016 943am by Shuraz Edited Dec 28th 2016 944am by Shuraz Thanks we already have all the recipe information attached to this item You can see all the recipe information if you are logged in as a premium member Volunteer Allakhazam Developer and Admin For real time update information on Allakhazam follow me on Twitter httpstwittercomgidono To make a Donation directly to me httpspaypalmeGidono So far I have received 2 donations Page top uses Jul 11 2018 at 732 AM Rating Good lovguild Scholar 101 posts Yea he was being nice to those that cant afford prem maybe Page top pigment Dec 10 2016 at 1114 PM Rating Decent Rysho 13 posts a petrifier cockatrice dropped this Vvampyr emarr Page top pigment Dec 12 2016 at 1001 AM Rating Excellent Gidono 5113 posts Rysho wrote a petrifier cockatrice dropped this Thanks added Volunteer Allakhazam Developer and Admin For real time update information on Allakhazam follow me on Twitter httpstwittercomgidono To make a Donation directly to me httpspaypalmeGidono So far I have received 2 donations Page top Droped Dec 09 2016 at 355 PM Rating Decent korika Scholar 286 posts Droped one from a plaguebone skeleton Cookie Antonius Bayles rangeress httpeqtoonxfreefr Page top Droped Dec 10 2016 at 237 PM Rating Excellent Gidono 5113 posts korika wrote Droped one from a plaguebone skeleton Thanks Which zone Volunteer Allakhazam Developer and Admin For real time update information on Allakhazam follow me on Twitter httpstwittercomgidono To make a Donation directly to me httpspaypalmeGidono So far I have received 2 donations Page top Sibilisan Viridian Pigment Dec 02 2016 at 300 PM Rating Decent Horlaora 2 posts Had one drop off of a chokidai elder in Gates of KorSha Page top Sibilisan Viridian Pigment Dec 02 2016 at 357 PM Rating Excellent Gidono 5113 posts Horlaora wrote Had one drop off of a chokidai elder in Gates of KorSha Added thanks Volunteer Allakhazam Developer and Admin For real time update information on Allakhazam follow me on Twitter httpstwittercomgidono To make a Donation directly to me httpspaypalmeGidono So far I have received 2 donations Page top Sibilisan Viridian Pigment Nov 30 2016 at 309 AM Rating Decent wizard1957 12 posts just had 1 of these drop from a_plaguebone_skeleton in lceanium Page top Sibilisan Viridian Pigment Nov 30 2016 at 151 PM Rating Excellent Gidono 5113 posts wizard1957 wrote just had 1 of these drop from a_plaguebone_skeleton in lceanium Thanks added Volunteer Allakhazam Developer and Admin For real time update information on Allakhazam follow me on Twitter httpstwittercomgidono To make a Donation directly to me httpspaypalmeGidono So far I have received 2 donations Page top Free account required to post You must log in or create an account to post messages

B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Wearables Carl Edmond Launches First Global Advertising Campaign By Daryl Crowther On Mar 19 2018 0 Luxury Swedish watch brand Carl Edmond launched their first global campaign today The advert features Joel Kinnaman as the face of the brand The company launched in September last year with an aim to bring together Swiss sophistication and Swedish heritage To design the watches they brought in Swiss watch designer Eric Giroud along with his protégée Adrian Glessing Together these highly respected designers created a minimalist aesthetic and a series of classy colour palettes To market the watches the company have created namesake character Carl Edmond a man who personifies the watches Swedish actor Joel Kinnaman was brought on board straight away to portray the character The campaign launched today with the release of the full video in which a series of people talk of their admiration for Carl Edmond He is portrayed as a man of almost mythical status Carl Edmond is an adventurer an explorer a vagabond and a diplomat living a life extraordinary to the fullest deluxe Carl Edmond Founder Ali Nouri says Id love to be more like Carl In recent years Swedish actor Joel Kinnaman has been making a name for himself stateside After landing a starring role in AMCs the killing he went on to play the titular role in the 2014 Robocop remake He currently plays Will Conway in House of Cards joining the successful Netflix series for its 4th season as well as playing the lead role in another Netflix series the scifi themed Altered Carbon If I was stranded on a deserted island and could bring one thing only I would bring Carl Edmond And if it was the other way around I would beg Carl to bring me says Joel In designing the range of Carl Edmond watches Giroud and Glessing took inspiration from Swedish furniture of the 1960s and 70s Unlike Swedish furniture however I am assured the watches will not need assembly once purchasedThe leather used to create the wristbands is Swedish Tärnsjö This 140 year old institution is part of a small minority of tanning houses that use the environmentally friendly vegetablebased tanning method The watches utilise Swiss quartz movement and sapphire crystal available in two shapes the round classic Ryolit and the bold square Granit The dials are available in a range of colours including white black gunmetal cameo navy and limed spruce Your browser does not currently recognize any of the video formats available Click here to visit our frequently asked questions about HTML5 video Carl Edmond Joel Kinnaman 0 ReddIt Daryl Crowther Prev Post Googles Magenta Team Creates AI NSynth Super Synthesizer Next Post Master Dynamic and Leica Continue Partnership With New Silver Edition You might also like More from author

O B I O O B I I O O O O O O O O O O O O B I O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

carl edmond
global advertising campaign
joel kinnaman


Extension Contact your local county Extension office through our County Office List Online Directory CSU Extension A division of the Office of Engagement Providing trusted practical education to help you solve problems develop skills and build a better future Established 1912 Home Topic Areas Publications About Us News Español Store Recognizing Tomato Problems 2949 Print this fact sheet by S Newman and L Pottorff 513 Quick Facts Tomatoes are an easy and popular vegetable to grow Tomato problems may be caused by nutrient deficiencies diseases fungi or insects Assess the symptoms then make the appropriate treatment Good cultural practices can reduce or eliminate many problems Despite the short growing season in many areas of Colorado tomatoes are an easy and popular vegetable to grow For healthy tomatoes Improve garden soil by adding organic material such as compost Use diseaseresistant varieties Eliminate competition from weeds Keep the plant growing vigorously with proper water and nutrients Keep the garden clean of plant debris Rotate crops Space plants for maximum air circulation Monitor for pests Failure to follow one or more of these steps can lead to pest problems To manage pests identify the source of the problem by assessing the symptoms The key in Table 1 will help you narrow down the cause It is organized by affected plant parts leaves stems roots and fruit Figure 1 Phosphorous deficiency Figure 2 Psyllid damage Figure 3 Evidence of flea beetles Figure 4 Tomato hornworm Figure 5 Symptoms of early blight Figure 6 Aphids Common Tomato Problems Phosphorus deficiencies Figure 1 occur early in the growing season when soil is still cool Phosphorus is abundant in our soils but may be unavailable to the plant when the soil is too cold Dont plant tomatoes too early in the season Use plastic mulch to warm the soil Once soil temperatures rise the problem usually corrects itself Curly top virus is transmitted by the beet leafhopper This problem is common in western Colorado but seldom found in eastern Colorado Infected plants turn yellow and stop growing Upper leaflets roll and develop a purplish color especially along the veins Leaves and stems become stiff fruit ripens prematurely It is difficult to control because leafhoppers migrate from southern areas Hot dry springs with predominantly southwest winds usually indicate increased problems with this disease No chemical controls are effective Use row covers to protect tomato plants from the leafhopper Psyllids Figure 2 are more commonly found in eastern Colorado and are seldom a problem in western Colorado They feed on tomato or potato plant sap and inject a toxic saliva that causes the characteristic psyllid yellows Leaves turn yellow veins often turn purple Stems may become distorted giving the bush a zigzag appearance To confirm psyllids check the undersides of leaves for nymphs Nymphs are about the size of an aphid At first they are yellow then they turn green They are sedentary while feeding and secrete small white granules that resemble sugar For best control dust the foliage especially Potato and Tomato Psyllids Flea beetles Figure 3 are small black or brown beetles that jump when disturbed The adults chew small holes or pits in leaves Wounded tissue may be more susceptible to diseases such as early blight Most plants outgrow flea beetle damage Insecticides such as cabaryl or permethrin are effective controls if needed See 5592 Flea Beetles Tomato or tobacco hornworms Figure 4 are large green or graygreen caterpillars with white to tan vshaped or dashed markings on their sides A green to reddish horn protrudes from the hind end They are voracious feeders stripping leaves from stems and even eating unripe fruit Pick them off by hand The caterpillars are susceptible to Bacillus thuringiensis Bt as well as to many common vegetable insecticides Early blight Alternaria leaf spot Figure 5 is caused by the fungus Alternaria solani Symptoms become prevalent during the hotter months This disease produces brown to black targetlike spots on older leaves If severe the fungus also attacks stems and fruit Affected leaves may turn yellow then drop leaving the fruit exposed to sunburn Sanitation is the best control Remove all diseased plant tissue on the ground as the fungus overwinters on leaf debris Do not plant tomatoes in the same place next year Space plants farther apart to improve air circulation Avoid overhead irrigation If the infestation is heavy sulfur dust may help protect new leaves from infection Septoria leaf spot is less common in Colorado than early blight It too is a fungal disease Characteristic symptoms are white or gray spots on leaves surrounded by a black or brown margin Control is similar to early blight Whiteflies and aphids Figure 6 both cause leaf yellowing and leave a characteristic sticky excrement called honeydew Leaves appear shiny and are somewhat sticky when honeydew is present Damage usually is minimal on tomatoes and often can be ignored If aphids become a problem some applications of insecticidal soap are quite effective Cucumber mosaic virus and herbicide injury are almost impossible to tell apart without previous knowledge of chemicals applied or laboratory confirmation Cucumber mosaic virus causes tomato plants to yellow and become bushy and stunted Leaves may be mottled The virus most often is carried in tomato seeds Mechanical transmission by workers touching plants and movement by aphid carriers can occur but this is much less common in tomatoes than in cucurbits Remove and destroy plants There are no chemical controls Figure 7 Fusarium wilt Fusarium wilt and Fusarium crown rot symptoms Figure 7 begin as yellowing of older leaves With Fusarium crown rot the leaves often turn brown or black and eventually wilt With Fusarium wilt the yellow leaves turn downward and droop Fusarium oxysporum the cause of both diseases is a common tomato fungus that lives in the plants vascular system which carries water from the roots to the leaves To see if either of these diseases is present Check watering practices Both over and underwatering can mimic disease symptoms Check the roots Discolored roots indicate root rot Cut the lower or main stem and look inside at the vascular tissue Fusarium wilt causes a dark brown discoloration within the vascular tissue Fusarium crown rot causes a rot or canker at the base of the stem and possibly a root rot Most tomato seeds or transplants are labeled with a code such as VFN VFNA VFNT etc This indicates that the plants are resistant to Verticillium wilt V Fusarium wilt F southern rootknot nematode N early blight A or tobacco tomato mosaic virus T Verticillim wilt and root knot nematodes rarely cause a problem in Colorado but if you have had a Fusarium wilt problem in the past it would be a good idea to choose a variety labeled F Do not plant tomatoes potatoes or eggplant in the affected area for two or three years No fungicides are labeled for Figure 8 Bacterial canker Figure 9 Tomato spotted wiltimpatiens necrotic spot Bacterial canker Figure 8 occurs sporadically in Colorado Symptoms begin with lower leaves turning downward Dark to light brown streaks may develop on the leaf midribs and eventually extend down the petiole to form a canker on the stem There may be vascular discoloration Symptoms on fruit are small white scabby raised lesions often described as birds eye This disease is difficult to distinguish from other tomato diseases and may need laboratory confirmation If identified destroy the plants Do not compost plant material Do not plant tomatoes potatoes or eggplant in the same soil for two to three years Tomato spotted wiltimpatiens necrotic spot tospoviruses TSWV or INSV Figure 9 has traditionally been a problem in commercial tomato production Recently however the disease has increasingly been found in home gardens Symptoms begin as dark brown to purple spots on leaves The dark areas spread to stems forming cankers Stem streaking also may be noticed Wilting symptoms gradually develop as the disease spreads However the leaf tissue is stiff not limp The most noticeable symptoms are yellow rings or spots on fruit Fruit may be distorted TSWV and INSV are moved from plant to plant by western flower thrips The only way to manage the disease Greenhouse Plant Viruses TSWVINSV Root rot can be caused by several fungi However poor soil drainage and overwatering are always involved For home gardeners control of a potential root rotting fungus is almost impossible Therefore management of root rot requires soil improvement proper watering and rotation of tomatoes Plant tomatoes and related species in the same garden spot only once every three years Figure 10 Catfacing Figure 11 Blossom end rot Figure 12 Sunscald on tomato fruit Catfacing Figure 10 is a term that describes tomato fruit that is misshapen with scars and holes in the blossom end The cause is thought to be cold weather during blossoming and perhaps high levels of nitrogen To manage it avoid setting out transplants too early in the season Blossom end rot Figure 11 begins as light tan watersoaked lesions on the blossom end of the fruit These lesions enlarge and turn black and leathery The cause is thought to be a combination of cold temperatures or excessive heat during blossom set and fluctuations in water supply When these two factors occur simultaneously calcium often becomes unavailable to the plant Hence a calcium deficiency occurs during fruit formation To manage the problem fertilize and water properly Avoid setting out transplants too early in the season Use mulch to help reduce fluctuations in moisture levels Stink bugs cause spots and internal damage to tomato fruit by their feeding Adults are shieldshaped and brown or green with red pink or yellow markings They release an offensive odor when handled Control weeds around the tomato patch as these insects overwinter in such areas Stink bug damage on green fruit appears as dark pinpricks surrounded by a light discolored area As fruit ripens these spots may remain green or turn yellow The tissue underneath is white and spongy Cavities may form under the damaged skin Sunscald Figure 12 is common on fruit exposed to too much sun This problem often occurs when infestations of hornworms are high and defoliation or pruning of leaves is heavy To help control sunscald shade the plant and reduce the fruits exposure to the sun Greenyellow shoulders develop on ripening fruit possibly due to high temperatures Chlorophyll in this area is slow to break down and results in a patch that remains green or turns yellow but not red This problem may affect the entire shoulder or only a small irregular patch Shade the plant and take other precautions to reduce the fruits exposure to the sun Table 1 Key to the identification of tomato problems LEAVES Purple leaves Leaves with purple veins and overall purplish tint Early season cool temperatures No insects present Phosphorus deficiency Leaflets roll upward and develop a purplish color especially along the veins Curly top virus Yellowed leaves Slight distortion purpling of veins Zigzag stem and branching pattern Check underside of leaves for insects Psyllids infected plants turn yellow and soon stop growing Curly top virus Small holes approximately 05 mm Flea beetle Chewing injury on leaves Tomatotobacco hornworm Black or dark brown spots Lesions have margins or concentric rings Lower leaves commonly affected Early blight Alternaria Spots on leaves with white or gray centers surrounded by dark black or brown margins Septoria leaf spot Honeydew produced and white insects fly away black rosy or green insects present Whiteflies Aphids Leaf scorching Check watering ambient temperature salts etc No signs of insect or disease present Check stems roots and vascular system Vascular system discolored See wilting section Distorted leaves Curling shoestringing cupping and herbicides applied recently plants stunted no herbicides applied Herbicide injury Cucumber mosaic virus Wilted leaves Check roots for rot and cut the stem to look inside the stem tissue Vascular streaking evident along entire length of stem Fusarium wilt Vascular streaking evident only in the crown first 12 inches of stem Fusarium crown rot Lower leaves turn down leaf edges brown Bacterial canker Leaf spotting concentric rings and necrotic dead leaf margins may or may not be present leaf tissue stiff not flaccid Tomato spotted wilt virusimpatiens necrotic spot virus No vascular streaking Check roots and soil moisture Roots discolored mushy See root section STEMS Black or dark cankers on stem Submit samples to a diagnostic clinic for confirmation Early blight Alternaria tomato spotted wilt virusimpatiens necrotic spot virus bacterial canker ROOTS Roots discolored mushy Check soil moisture and watering Root rot caused by one of several common fungi FRUIT Spots circles or blotches Ring spots on fruit Tomato spotted wilt virusimpatiens necrotic spot virus Dark pinpricks surrounded by a light discolored area on green fruit These areas turn yellow or remain green on ripe fruit The tissue under the spots is white and spongy and remains firm as the fruit ripens Stink bug feeding White leathery areas Sunscald Blotches on the shoulder of the fruit Greenyellow shoulders Small white to yellow raised blotches on fruit often called birds eye Bacterial canker Distorted Yellowing or not with necrotic areas or not Catfacing Blossom end flattened and black Blossom end rot Yellowing Psyllids Ring spots on fruit Tomato spotted wilt virusimpatiens necrotic spot virus Contact your Colorado State University Extension county office for more information or for help identifying problems 1 S Newman Colorado State University Extension specialist greenhouse crops and professor Originally written by Laura Pottorff former plant pathologist and horticulturist Integrated Pest Management Program Jefferson County 600 513 Colorado State University US Department of Agriculture and Colorado counties cooperating Extension programs are available to all without discrimination No endorsement of products mentioned is intended nor is criticism implied of products not mentioned Go to top of this page

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

tomatoes
phosphorus deficiencies
curly top virus


Lifes Blood CLASS NOTES Rh SYSTEM History In 1939 Hemolytic Disease of the Newborn was first described by Levine and Stetson The cause of hemolytic disease of the cause was not specifically identified but maternal antibody suspected A year later 1940 Karl Landsteiner and Alexander Wiener injected animals with Rhesus monkey cells to produce an antibody which reacted with 85 of human red cells which they named antiRh Within a year Levine made connection between maternal antibody causing HDN and antiRh Between 194345 the other common antigens of the Rh system were identified For many years the exact inheritance of the Rh factors were debated Weiner promoting Rh and hr terminology and FisherRace utilizing DCcEe for the various Rh antigens In 1993 Tippett discovered true mode of Rh inheritance using molecular diagnostics Rh Antigens D Rh o is the most important antigen after A and B antigens Unlike the antiA and antiB antibodies antiD antibodies are only seen if a patient lacking D antigen is exposed to D cells The exposure of D cells usually occurs through pregnancy or transfusion There are 5 principle antigens that may be found in most individuals They are D found in 85 of the population C found in 70 of the population E found in 30 of the population c found in 80 of the population e found in 98 of the population d which has never been identified but refers to the 15 of the population who has no D antigen There are at over 50 Rh antigens that have been identified including those that are either combinations of these antigens or weak expressions of the above antigens but most Rh problems are due to D C E c or e Alleles The common alleles are C and c are alleles with C w occasionally seen as a weaker expression of C E and e are alleles although E is seen only a third as often as e The e antigen is referred to as a high incidence antigen since it is found in 98 of the population D and the lack of D or d are alleles Characteristics of Rh antigens The Rh antigens together are proteins of 417 amino acids These proteins cross the red cell membrane 12 times There are only small loops of the protein on the exterior of the cell membrane Therefore the Rh antigens are not as available to react with their specific antibodies and there are fewer antigen sites than ABO Unlike the ABO system the Rh antigens are not soluble and are not expressed on the tissues They are well developed at birth and therefore can easily cause hemolytic disease of the newborn if the baby has a Rh antigen that the mother lacks Besides the antigens being welldeveloped at birth they are very good immunogens This is especially true to D which if the most immunogenic after A and B antigens Rh Antibodies Unlike the ABO antibodies that are mainly IgM the Rh antibodies are commonly IgG They are NOT naturally occurring and therefore are formed by immune stimulus due to transfusions or babys red blood cells during pregnancy The most common antibody to form is antiD in Rh negative individuals Since Rh antibodies are IgG they bind best at 37 o C and their reactions will be observed with the indirect antiglobulin technique Agglutination reactions are enhanced by high protein albumin lowionic strength saline LISS proteolytic enzymes ficin and polytheylene glycol PEG Rh antibodies will react more strongly with homozygous cells than with heterozygous cells For example an antiE will react with strongly with EE cells and more weakly with Ee cells This is called dosage Both Hemolytic Disease of the Newborn and Hemolytic Transfusion Reactions can occur due the various Rh antibodies AntiD has been the biggest concern since it was recognized in the 1940s as being the most common cause of hemolytic disease of the newborn Since the D antigen is so immunogenic we screen all donor units for the D antigen Therefore if an individual is A it means both the A and the D antigens are present On the other hand if an individual is A the A antigen is present and the D antigen is absent To prevent problems due to antiD we try to always give Rhnegative individuals Rhnegative blood and we give Rh o immune globulin to Rhnegative mothers to prevent the formation of antiD during pregnancy The incidence of Rh antibodies AntiD most common antibody seen in RhD negative people AntiE most common antibody seen in Rh pos people since only 30 of the population have the antigen AntiC or Antic less common most people have the antigen Antie often seen as autoantibody and will make it difficult to find compatible blood since 98 of the population have the e antigen AntiCe or AnticE often seen in combination If a patient lacks both a C and e and has made an antiC then enhancement techniques should be done to make sure that an antie is not also present Rh System Inheritance From the 1940s to the 1990s the mechanism for inheritance of the Rh Blood Group System was in question The terminology that is part of the FisherRace Theory is most commonly used even today FisherRace Theory The FisherRace theory involved the presence of 3 separate genes D C and E and their alleles c and e and the absence of D since an antid has never been found These three genes are closely linked on the same chromosome and are inherited as a group of 3 The most common group of 3 genes inherited is CDe and ce D negative is the second most common Weiner Theory Weiner believed there was one gene complex with a number of alleles resulting in the presence of various Rh antigens According to Weiner there were 8 alleles R o R 1 R 2 R z r r r r y which ended up with different antigens on the red cells that he called Rh o rh rh hr hr Weiner terminology is not use as often today but you will often see Rh o D when a person considered to be Rhpositive At times the gene terms are easier to use than FisherRace If a person has the FisherRace genotype of DCeDCe it is easier to refer to that type as R 1 R 1 2 Made up of combinations of genetic products Tippett Theory In 1986 Tippett predicted that there are two closelylinked genes RHD and RHCE The RHD gene determines whether the D antigen that spans the membrane is present Caucasians who are D negative have no gene at that gene loci In the Japanese Chinese and Blacks of African descent have an inactive or partial gene at this site The RHCE gene determines C c E e antigens produced from the alleles RHCe RHCE RHcE RHce Rh Gene Complexes Antigens Possible Combinations and Percentages Haplotypes Genes Present Antigens Present Phenotype Percentage R 1 RHD RHCe DCe R 1 42 r RHce dce r 37 R 2 RHD RHcE DcE R 2 14 R o RHD RHce more common in Blacks Dce R o 4 r RHCe dCe r 2 r RHcE dcE r 1 R z RHD RHCE DCE R z 1 r y RHCE dCE r y 1 Translating From Wiener To FisherRace There are times when you will need to convert Weiner to FisherRace or vice versa It will be easier to do these conversions if you remember the following R always refers to D whether it is R o R 1 R 2 or the very rare R z r always refers to the lack of D o refers to having no C or E 1 or always refers to C 2 or always refers to E The very rare haplotypes that have both a C and E are given letters from the end of the alphabet z and y Determining Genotypes From Phenotypes The following steps will be helpful in determining from the individuals phenotype These rules are based on probability so the least likely genotypes will involve R z or r y Type patient for the five Rh antigens D C c E e Start with D is it positive or negative If negative the individual will be homozygous d If positive for D you cant tell yet whether the individual is homozygous or heterozygous for D Therefore put D on just one chromosome Look at C is it positive or negative If negative put c on each chromosome If positive look at c result to determine if the C is homozygous or heterozygous If there is no c present there would be two C and it would be homozygous If a c is present as well as C they are heterozygous If homozygous then put C on each chromosome If heterozygous put C on same chromosome as D put c on other Look at E is it positive or negative If negative put e on each chromosome If positive look at e result to determine if homozygous or heterozygous If homozygous put E on each chromosome If heterozygous put E on same chromosome as the D unless the D already has a C put e on other chromosome DCe is more common than DcE and DCE is extremely rare Put C and E together on same chromosome only if no other possible combinations Most Common Genotypes The following genotypes are listed as the most common with 1 being the most common in Whites and 7 the least common R z and r y are so rare they are not included in the following table Incidence of the most common genotypes Antigens Present Genotype Incidence DCE Weiner Haplotypes Whites Blacks 1 D C c e DCece R 1 r 311 88 DCeDce R 1 R o 34 15 DceCe R o r 02 18 2 D C e DCeDCe R 1 R 1 176 29 DCeCe R 1 r 17 07 3 ce cece rr 15 7 4 DCcEe DCeDcE R 1 R 2 118 37 DCecE R 1 r 08 01 DcECe R 2 r 06 04 5 DcEe DcEce R 2 r 104 57 DcEDce R 2 R o 11 97 6 Dce Dcece R o r 30 229 DceDce R o R o 02 194 7 DcE DcEDcE R 2 R 2 20 13 DcEcE R 2 r 03 01 Applications of Rh genotyping Paternity testing of the blood group antigens is based on a process of exclusion Since the RHD and RHCE are closely linked and Ce ce cE are produced by a single gene there are limited combinations that the father can provide HDN predictability by testing the fathers Rh genotype This helps predict likelihood of HDN due to D when mom has antiD The most common Rh genotype of the father will indicate whether the baby has O 50 or 100 probability of being D positive If the father is also D negative cece the baby will be D negative as well and there is a 0 probability of the baby suffering from Rh o HDN If the fathers Rh genotype appears to be either R 1 r R 2 r or R o r the baby has a 50 probability of being D positive and suffering from Rh o HDN On the other hand if a fathers Rh genotype appears to be any of the following R 1 R 1 R 2 R 2 R 1 R 2 R o R o R 1 R o or R 2 R o the baby has a 100 probably of getting a D gene from his father and therefore being D positive and suffering from Rh o HDN Variants Weak D D u Weak D is a weakly expressed D antigen that will only be demonstrated after incubation at 3537 o C followed with antiglobulin testing ie being demonstrated only by Coombs technique An Rh control must always be run along with the weak D test Always consult the product insert to determine if Rh Control needs to be run when performing the immediate spin D testing The following results could be obtained when performing the D testing Immediate Spin 37 o C AntiD AGT Interpretation AntiD Rh Co AntiD Rh Co AntiD Rh Co 0 D positive 0 0 0 0 0 Weak D 0 0 0 0 0 0 True D negative 0 0 0 0 Or any time the Rh control is positive you can not interpret the results and need to perform further testing Testing for Weak D AABB requires that all donor blood that originally fails to react with antiD at immediate spin must be tested for weak D Units that test weak D positive would be labeled D positive and would be transfused only to D positive individuals Hospitals may or may not test all Rh negative recipients for weak D The cost of time and reagents is minimized if only the immediate spin This may create some confusion with the recipient if their donor card indicates they are Rh positive but they type Rh negative when they are the recipient Recipients that type D negative at immediate spin would be given D negative blood which not create a problem for the patient When performing testing prenatal and postnatal mothers Dnegative blood at immediate spin would be tested for weak D as well to determine if they are eligible for Rh o Immune Globulin Since Rh o Immune Globulin is actually antiD it is safe for a true D negative but not for a weak D positive mother Why do weak Ds exist There are three explanations for weak Ds Quantitative Weak D There are individuals that quantitatively produce fewer D antigen sites This is more common in Blacks and is often seen with the Dce haplotype On rare occasions among Whites an unusual DCe or DcE may also produce a quantitatively decrease weak D Position Effect Weak D In this case the D is weakened by the position of a C on the opposite haplotype which is called the trans position The two Rh genotype combinations where this type of weak D is seen are DceCe and DcECe Today this type of weak D would type as a regular D due to the improvement of reagents Partial D antigen Mosaic D It has been found that some Dpositive individuals make an alloantiD that reacts with other D positive cells but not their own Many of these will demonstrate a weak D type of reaction In this type of weak D the individuals are lack some of the components of the D antigen and therefore are able to make allantibodies to those specific components if they are transfused with D positive blood Other Rh System Variants There are presently 46 Rh antigens identified and named The following are the most common of those variants C w is a low frequency antigen found in approximately 2 of Whites and 1 of Blacks It is not an allele of C and c Its allele is MAR which is found in 999 of the population V and VS are low frequency alleles found in 1 or less of the Whites but are more common in Blacks V is found in 30 of the Blacks and VS in 32 G is present when D or C present due to the present of serine at the 103 position of the Rh polypeptide AntiG will react with both D and C cells f is present when c and e together on same chromosome Dce or ce This is the most common of what are called cis product antigens Rh null has no Rh antigens on their red cells but these individual can transmit normal Rh antigens to their offspring In the most common type the core Rh polypeptide is missing A less common type has the regulator gene that turns off the expression of Rh There have been at least 43 individuals in 14 families that are Rh null In these individuals the red blood cell membrane is abnormal and some of these have been identified when it was observed that they had hemolytic anemia and abnormal red cell morphology If these individuals develop an Rh antibody following a transfusion or pregnancy it is considered a antitotal Rh antibody Rh Typing False Positives False positive Ds occur When following through to AGT for weak D and will be identified as false positive by a positive Rh control This is seen when a patientdonor has strong positive DAT The cells are coated with antibody not necessarily Rh antibody in vivo Albumin is necessary in reagent AntiD to overcome the zeta potential allowing cells coated with IgG AntiD to get close enough together to agglutinate but cells coated in vivo with any IgG antibody will also agglutinate in albumin These false positives are corrected by using form of AntiD that does not require albumin There are two types of alternative types of antiD Monoclonal IgM antiD will cause agglutination of D positive cells without the presence of albumin at room temperature A number of facilities normally use this type of antiD and therefore do not routinely use Rh control Chemically modified antiD has been modified by breaking the disulfide bonds closest to the hinge region so antibody can reach cells that are farther apart False positive can also be caused by rouleaux formation which will look like agglutination macroscopically Rouleaux would be identified microscopically due to the coinstacking appearance of the red cells This false positive would be corrected by washing cells 3 to 4 times and then retesting False Negatives False negatives are not readily identifiable but can occur in the following instances The most common is the result of too heavy cell suspension due to too many cells for the amount of antibody in the antisera They may also rarely be caused by extremely strong positive DAT In this case a the patients D antigen sites are coated in vivo and there are no sites left for commercial antiD to attach to This can be fixed by heating cells gently to elute off antibody without damaging cells then retest OBJECTIVES Rh SYSTEM Briefly describe how and when the Rh system was discovered List the major Rh antigens and state the frequency each is seen in the Caucasian population Describe the characteristics common to the major Rh antigens and compare them to the ABO system Explain the Tippett theory of inheritance For any given Rh phenotype predict the most likely genotype in both the Wiener and FisherRace nomenclatures For any given Wiener genotype list the Rh antigens present Explain why Rh genotyping is important Give three explanations for the weak D phenotype Discuss how the weak D phenotype applies to donors recipients and obstetrical patients State the relative frequencies of the Cw V and VS antigens Explain the G f and Rh null phenotypes Describe characteristics common to antibodies in the Rh system List the more common antibodies seen in the Rh system Discuss the use of albumin and enzymes in identifying Rh antibodies Explain how false positives can occur when testing for the Rh antigens and describe how the problem may be overcome Explain how false negatives can occur when testing for the Rh antigens and describe how the problem may be overcome Differentiate between highprotein antiD chemically modified antiD and saline antiD Performance objectives Correctly perform interpret and record the Rh type of any given sample Recognize when chemically modified or saline Rh reagents must be used Correctly perform interpret and record a weak D D u test Correctly perform interpret and record the Rh phenotype of any given sample and state its most likely genotype

O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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