Distributed video coding (DVC) is a relatively new video coding architecture originated from two fundamental theorems namely, Slepian–Wolf and Wyner–Ziv. Recent research developments have made DVC attractive for applications in the emerging domain of wireless video sensor networks (WVSNs). This paper reviews the state-of-the-art DVC architectures with a focus on understanding their opportunities and gaps in addressing the operational requirements and application needs of WVSNs. Rapid advancements in computing hardware and data communication have provided a platform to develop and deploy several innovative services and systems. The concept of spatially distributed battery powered sensors that cooperatively deliver their sensed information using radio channels to some common location has eventually taken the form of a wireless sensor network (WSN). Such a networked sensing infrastructure can enable a wide spectrum of applications ranging from military systems with advanced scouting and surveillance capabilities to civilian systems for environment and health monitoring, person locator services, detection of malfunctioning machinery in industrial plants, and inventory control.Recently, wireless video sensor networks (WVSN) and their associated theoretical and practical challenges have drawn significant attention from the research community. Such growing interest can be attributed to new applications enabled by large-scale networks of small camera devices capable of capturing visual information from their surrounding environments, performing simple processing/compression on the captured data, and transmitting it to remote locations (e.g. base stations) as shown in Fig. Video compression is a relatively complex operation that can consume significant processing and energy resources in resource-limited camera sensor nodes. Conventional compression standards are computation intensive but perform very well when complexity of the encoder is not a major concern. DVC is an emerging video coding paradigm for applications with limited resources available at encoder. It reverses the conventional video coding paradigm by shifting the encoder’s complexity entirely or partially to the decoder, which is assumed to be more resourceful than the encoder  and interframe predictive video coding (PVC) frameworks. These frameworks allocate codec functionalities such that most of the high complexity operations that involve exploiting spatial and temporal correlation, e.g. motion estimation and compensation, are executed at the encoder, while the decoder performs lower complexity operations such as entropy decoding, frame prediction, inverse quantization, and DCT on the bitstream received from encoder  which contains a high degree of temporal redundancy among adjacent frames. Each frame is divided into sub-blocks for coding purpose. Conventional video coding employs two primary coding modes  and decoder (simple), with the complex motion search operation dominating the overall encoder’s complexity.Drift error Since no real-time synchronization channel exists between PVC encoder and decoder, there is a higher probability of prediction mismatch in uncontrolled environment such as communication over wireless/radio links which are more prone to channel errors.Irrespective of the coding modes, the PVC architecture has two significant drawbacks  be exploited at decoder given that the bitstreams received from multiple encoders performs joint decoding via analyzing statistical correlation between them. It should also be noted that the term The shift of complexity in DVC is accomplished by assigning to the decoder the responsibility for generating the prediction, and relieving the encoder from such complex and computation intensive task. However, the encoder still possesses the ability to select the best prediction based on a comparison with the original frame to be coded. On the other hand, the decoder is unable to perform such comparison since it has only access to already decoded information and not the original frame, which complicates the decoder’s task to estimate a precise motion field as compared to conventional predictive video coding.To reliably deliver high quality video to the sink server (decoder) in energy-constrained WVSN, the use of energy-efficient video coding scheme, rate-control and QoS management algorithms is critical. With a competitive compression performance and lower energy consumption, DVC is a promising alternative to traditional PVC architectures which are not suitable for WVSNs.In this paper, a comprehensive review of the state-of-the-art on DVC based architectures appropriate for WVSN is presented for the first time. The review includes a comparative discussion of several well-known architectures in literature with a focus on their functional aspects, performance comparison and suggests a number of possible enhancements to the design of these architectures.The rest of the paper is organized as follows: “A WVSN is a network of spatially distributed sensor nodes, each equipped with a miniaturized camera that captures, compresses, and transmits visual information (image/video) about its surroundings to a sink node or base-station for further content analysis and distribution. The foundation of WVSNs can be understood as the convergence between the concepts of WSNs and distributed smart cameras, i.e. it encompasses technologies from various disciplines such as wireless communications and networking, signal processing, security, computer vision, control and robotics .Problem definition Assume X and Y are two statistically correlated, independently and identically distributed (i.i.d) video sequences from two separate encoders that are aware of the existence of each other. Moreover, the decoder has complete information about the encoders. The problem is to determine the minimum encoding (bit) rate for each of the video sources such that their joint decoding at the decoder reconstructs each of the video sequence with sufficient accuracy. This problem can be addressed using joint entropy, since video sequences X and Y are statistically correlated. Two different methods to reconstruct them are as follows:X and Y are encoded together to exploit their statistical dependencies, the minimum lossless rate is H, which represents their joint entropyIf the two statistically dependent video sequences X and Y are encoded independently, their respective encoding rate is:H(X), and H(Y), represents the entropyX, and Y, respectively.However, if the video sequences mentclass2pt{minimThen the required encoding rate is given by:H(X) and H(Y). Distributed source (video) coding provides an answer to this problem as follows:The functional block diagram of PVC and DVC architectures is shown in Fig. Slepian–Wolf theorem for lossless compression Assume that the minimum encoding rate for lossless reconstruction of signal H(X). To determine the lossless encoding rate between two (or more) related source signals X and Y, exploit the statistical correlation between these signals and encode them jointly with the joint signal entropy of X and Y, can be attained even if X and Y are encoded independently (neither X nor Y has access to each other), given that they will be jointly reconstructed at the decoder with an arbitrarily small error. The following set of equations represents the individual as well as joint encoding rates of signals X and Y:The Slepian–Wolf theorem  codes.Wyner–Ziv theorem for lossy compression Wyner and Ziv  have gained considerable attention in recent years due to their vast application domain, flexible deployment structure, and most of all, the availability of low–cost CMOS sensor modules. The application domain for WSN spans from surveillance monitoring to healthcare, traffic and industrial control sectors Yang . The selDifferent WSN applications may have different requirements in terms of bandwidth, processing and compression, among others. Video streaming involves continuous capturing and delivery of data that requires optimized encoding and compression algorithms in addition to efficient hardware to meet the often demanding QoS requirements  that include video sensing modules with on-board processing and transmission functionality. These integrated units are interconnected with each other via wireless networking protocol, communicate over radio links, and have limited battery life. They are used to capture, compress and transmit compressed video data from their surroundings to a centralize location (base-station) over single- or multi-hop environment. Applications such as mobile video calling, wireless video surveillance, and monitoring are belonging to the uplink application model , low-encoding complexity that in turn leads to low-power consumption, longer battery life, and light-weight processing devices  and receiver (decoding node) sides of the network. However, the middle tier, i.e. the transcoder, requires video to be encoded by conventional PVC based codec. The basic architecture of transcoder is shown in Fig. As discussed in “block-based encoding approach with motion estimation module at decoder. On the other hand, the Stanford architecture adopted a frame-based encoding approach, which has gained much popularity because of its comparatively better rate-distortion performance. Subsequently, enhancements were made to the original design such as the extension of pixel domain Wyner–Ziv (PDWZ) to transform domain Wyner–Ziv (TDWZ), replacement of turbo codes by LDPC channel codes, development of more efficient reconstruction algorithms, and employment of Intra-frame coding mode from state-of-the-art PVC architectures for more efficient generation of side information. In the following section, we discuss the three main DVC architectures as mentioned above in more detail, namely PRISM  architecture proposed by Puri and Ramchandran  was desiEach video frame is first decomposed into non-overlapping blocks of size Transform coding 2D discrete cosine transform (DCT) is employed to transform each macroblock from spatial to frequency domain with a computational complexity equivalent to that of performing Intra-frame coding. The transformation yields DCT coefficients for each of the macroblock that must be transformed into quantized codewords prior to encoding.Scalar quantization Let Y to be its side information generated from a previously reconstructed frame, and N is the correlation noise. In Fig. X while the next two lines represent the corresponding partitions of the quantized codeword space of X. The box shows the observed codeword which exists in the first partition. If the quantization step is less than the magnitude of N. The scalar quantization block generates the space for evenly distributing the quantized codewords for Syndrome encoding Following the quantization step, the quantized codewords are partitioned using Euclidean space Trellis channel code which operates on BCHRefine quantization In scalar quantization, the step size is lower bounded by the correlation noise N, which is crucial to avoid decoding errors  of the source sequence. The PRISM framework can adopt any of the reconstruction algorithms from spatio-temporal correlation interpolation to efficient extrapolation algorithms.De-quantizer and inverse transformation Following the reconstruction of the transform coefficients of the predicted source signal, de-quantization and inverse DCT transformation is performed to extract pixel values of the block.i − 1) bits are determined by the bits at previous levels i and j represents the coding bit, current coset level, and previous coset level, respectively, for 1 ≤ j ≤ i − 1). Therefore, quantization of X to the closest coset is done at the root level, which determines the path to the codebook of next level using partition tree that originally possesses the codeword for X. The encoded source bits are also determined by the codebook path and transmitted to the decoder. The total number of coset levels (and in turn the data rate) may vary depending on the distortion and noise that exist between the predictor and the received bitstream. Moreover, each coset level can be taken as a single level partition tree. In order to achieve the required rate for that level, a separate dedicated encoder and decoder can be designed. Although this slightly increases the complexity of the encoder, such a design allows the use of linear correction codes for each level and improves overall error resilience of the codec against channel and propagation errors.In  coding is implemented, which dynamically adapts to the coding parameters associated with mismatches that occur between the frame to be encoded and its side information. Each block of input symbols from the quantized stream is assigned a parity sequence and the blocks that have same parity sequence are grouped together in the same coset. Thereafter, the parity sequence is temporarily stored in buffer and transmitted in small chunks to the decoder as and when required. Such an arrangement ensures that the encoder will transmit only a small amount of parity bits to the decoder for reconstruction of quantized bitstream. However, the decoder continues to generate feedback requests until the quantized bitstream has been reconstructed with desired quality parameter.Frame interpolation model and side information generation Temporal interpolation between two successive key frames is performed to generate side information for the current frame to be decoded. However, the decoder design is flexible enough to adopt various interpolation techniques, ranging from simple average interpolation to complex symmetric motion vector (SVM) based motion compensation, which may include multiple frame predictors and intelligent segmentation features. The interpolation technique simply averages the pixel values of successive key frames to predict the pixel value of the non-key frame in between them at the corresponding location. However, SVM interpolates the motion based on the assumption that the motion vector remains the same between the successive key frames. Therefore, the block matching is performed between the successive key frames in order to estimate the symmetric motion vector for the given block of the sandwiched non-key frame. Next, the decoder performs statistical correlation between the frame to be decoded and the corresponding side information which is required for the conditional estimation of a given frame in the reconstruction module.Reconstruction Each pixel of the frame can be reconstructed provided that its decoded bitstream and side information are available at the decoder. Since symbols are grouped together in cosets associated with the levels of quantisation, therefore if the side information is close enough to the reconstructed signal resulting from the decoded bitstream, it may fall within one of the coset‘s bins. Alternatively, the reconstruction process relies only on the signal to be reconstructed, quantizes it to the bin boundaries and ignores the side information. Such scenarios may happen when there are high motion frames and various occlusions in place.q) which produces an estimate u) for the given frame (fi2) using the following reconstruction function:bu represents the pixel in M = q levels of quantization, respectively. The above expression states that if a pixel values lies within the quantization index boundaries, then u′ extracts its value from v, otherwise it chooses one of the boundary values near v.The turbo decoder accompanied by the side information Hyper-Trellis decoding for PDWZ video coding is proposed in .Discrete cosine transform (DCT) Each WZ frame is decomposed into sub-blocks which undergo DCT transformation and generate DCT coefficients. These DCT coefficients are assigned to different bands according to their position in the DCT block. Thereafter, each DCT band is quantized into a number of quantization levels via a uniform scalar quantizer.Bit-plane extraction Quantized DCT coefficients (symbols) are grouped together into bit-plane vectors and fed independently to the Slepian–wolf turbo encoder.Turbo encoding Turbo encoder starts encoding each bit-plane vector using rate-compatible punctured turbo (RCPT) codes  and scales (resolution). Any decomposition involves a pair of high or low frequency components (sub-bands) that correspond to the detailed parts, and smooth parts, of the video frame, respectively. The wavelets are represented as coefficients which are organized into multi-resolution levels. The main advantages of DWT over DCT are the absence of blocking artefacts as it works on the whole frame rather than on separate blocks, better de-correlation  property, and inherent scalability. However, popular wavelet coding schemes such as Embedded Zerotree Wavelet (EZW) and Set Partitioning In Hierarchical Trees (SPIHT) produce code words with variable length, which can make the compressed video streams very susceptible to transmission errors in wireless channels. The effects of these errors can in turn propagate to the entire frame during the video reconstruction  coding. The significant coefficients are turbo coded and the parity bits are transmitted. The significance map is intra-coded by an Entropy Coding module and transmitted to the decoder, which uses it to extract the significant coefficients of the side-information for reconstructing the WZ frames.Similarly, Guo et al.  presenteOver-Complete DWT module to transform a frame into subbands in an over-complete form to overcome the shift-variance problem of critically sampled DWT; (2) a Motion Refinement module to refine the motion vector by motion estimation between current and previous low frequency subbands, and use the refined motion vector to generate side-information of higher-frequency subbands at the same decomposition level. This process repeats until all levels are decoded.So far the new features introduced above are mainly at the encoder side. For the decoder side, Liu et al.  proposedIt is observed that the accuracy of side information generation has a significant impact on codec’s overall performance. Several enhancements have been suggested for the estimation of side information in TDWZ codec. This includes a progressive side information refinement framework introduced in  DCT-based intraframe coding where the even frames are encoded as I frames; (b) H.263+ interframe coding with an I-B-I-B predictive structure; and (c) PDWZ codec.The rate-distortion comparison among PDWZ, TDWZ and H.263+ video coding architectures reported in . If the decoder is involved in taking a decision about the encoding rate, feedback channel is required to provide a more sophisticated and tighter control over the number of bits transmitted from the encoder to decoder. Decoder performs complex processing during frame reconstruction, and depending upon the requirements to achieve predetermined target quality, the decoder may request the encoder to change its encoding rate. For example, parity bits transmitted from the encoder are analyzed by the decoder to determine whether these bits are insufficient to achieve an acceptable level of performance. If not, it will request additional parity bits from encoder, rather than using the decoded frames with well-built traces.Table Such approach is applicable to real-time video coding (active communication mode) applications because the decoder can estimate the number of additional bits required only at the time of decoding. Feedback channel also has an impact on decoder’s complexity and may introduce latency if used frequently. An improvement to the side information generation module may involve restricting the number of feedback requests from the decoder. Alternatively, the encoder rate-control approach eliminates the need for a feedback channel (passive communication mode) and estimates the number of bits needed to achieve the desired target quality with additional complexity at the encoder side. Berkeley’s PRISM architecture, and Stanford’s Wyner–Ziv architecture, are examples of encoder, and decoder based rate-control approaches, respectively.BCH, turbo and LDPC channel codes BCH channel codes with ability to correct multiple bit errors are very simple and have tighter control on symbol errors during the channel coding process. Decoding of BCH requires performing simple algebraic operations , the WZ bitstream and H.264  bitstream are sent separately to the decoder. However, for practical applications, a single transport bitstream that combines the compressed WZ and H.264 frames is required.Latency The conventional DVC codecs ideally assumes the block interleaver size in Slepian–Wolf turbo code is large enough to encode an entire WZ frame, which is unrealistic for practical use since it will add significant computational delay to the end-to-end system. Unlike the WVSN requirement, the system will be unable to respond with a timely WZ decoded output due to the intense Slepian–Wolf turbo coding and decoding delay.Bitrate allocation In most of the DVC codecs (PDWZ/TDWZ), the bitrate of WZ frame is determined by exploiting the statistical correlation between the side information and original WZ frame. Due to the architectural constraint, the encoder does not have access to side information. Therefore, the accurate estimation of the number of parity bits that will be sufficient for decoding is very complex. This rate control problem is commonly addressed by using the feedback channel between encoder and decoder. In case of decoding failure, a request for more parity bits will be sent to encoder via feedback channel. However, the request is unable to inform the encoder the number of parity bits that should be sent. Sending redundant parity bit increases the transmission energy consumption, a situation that will be exacerbated in multihop WVSN scenario. On the other hand, architectures without feedback channel usually compute the side-information at encoder to predict the bitrate, which results in greater computational complexity (and associated energy consumption) at the encoder that consequently decreases the lifetime of the source node and the entire network.Moreover, regarding DVC application to WVSN, there are still challenges to be overcome in order to enable the delivery of high quality video stream, such as:In our work presented in (Imran et al. We also investigated the lifetime of both source and relay nodes and the overall network for each of the video codecs. The relative order of the codecs in terms of the lifetime of the source node, which is considerably shorter than that of relay node and thus dictates the network lifetime, expectedly follows the computational energy results.Further findings on processing and memory requirements supported our assessment that DVC-based codecs outperform the conventional codec. The variation in the processing and memory requirements between the DVC-based codecs is primarily due to the GOP difference and the compression technique.In this paper, we reviewed and synthesized promising DVC architectures and the enhancements made to them in recent years. In addition, the significance of DVC in the evolving WSN application domain is discussed. Future research directions for DVC may include enhanced side information generation, rate-control, correlation noise modelling, as well as the design of novel and efficient channel codes. Enhancing target reconstruction quality, enabling flexible complexity distribution between encoder and decoder, and multi-view DVC coding are still open research issues that should be investigated.


For instance mice deficient for p53 spontaneously develop multiple tumors and an additional deletion of p21 lead to a significant reduction of thymic lymphomas [Δhepa mice model. The NF-κB pathway regulator NEMO  has been shown to control chronic inflammation and hepatocarcinogenesis in mice.This argues that the complete spectrum of p21 function during tumorigenesis is not clearly identified. The role of p21 has been further studied in the NEMOΔhepa), is of clinical interest as these animals develop a cascade of events which resemble the spectrum of human chronic liver disease, which leads from chronic hepatitis to liver cirrhosis and growth of hepatocellular carcinomas (HCC). Additionally, a recent study using human HCC tissue found a downregulation of NEMO in tumor tissue, further supporting the translational relevance of the NEMOΔhepa mice model [The hepatocyte specific deletion of NEMO  mice carrying a hepatocyte specific deletion for NEMO and an additional constitutional deletion for p21 were generated.The deletion of NEMO in hepatocytes triggers increased p21 expression ,6. In orΔhepa/p21−/− livers compared to NEMOΔhepa livers. This result was unexpected since p21 binds to CcnE/cdk2 and CcnA/cdk2 complexes thereby preventing progression from G1- to S-phase. Very likely the loss of p21 expression is compensated by other cell cycle inhibitors such as p-p27 and p18.Although p21 is a cell cycle inhibitor its deletion had no impact on cell proliferation in 8 week-old NEMOΔhepa livers, the cell cycle regulator CcnA2 and CcnE2 were overexpressed. However, recent studies discovered that ectopic overexpression of CcnA or CcnE in mouse embryonic fibroblast (MEFs) lead to an increase in DNA double strand breakage [Δhepa mice could be explained by elevated CcnA2 and CcnE2 expression. The DNA double strand breakage was quantified by pH2AX Immunofluorescence staining.Despite the unchanged cell cycle activity in p21 deficient NEMObreakage . TherefoΔhepa/p21−/− mice with Lipopolysaccharide (LPS) enhanced DNA damage massively compared to NEMOΔhepa mice. After LPS administration NEMOΔhepa mice suffer from severe liver injury which is reflected in the increased alanine aminotransferase (ALT) and aspartataminotransferase (AST) serum values and apoptotic cells in the liver of these mice. However, in NEMOΔhepa/p21−/− mice transaminases and cell death were significantly enhanced. Finally, this enhanced liver injury in the double knockout animals resulted in a higher lethality of this mice after LPS administration.p21 is not only protective against DNA damage in the chronic liver injury model as challenging double mutant NEMOΔhepa/p21−/− mice which carry in addition a deletion for the TNF receptor 1 (NEMOΔhepa/p21−/−/TNF-R1−/−), showed a strong attenuation of the DNA damage and cell death.The observed hypersensitivity against LPS due to the lack of p21 is mediated via the Tumor Necrosis Factor (TNF), since NEMOΔhepa/p21−/−) showed enhanced hepatocyte proliferation as revealed by Ki67 staining. This resulted consequently into a higher liver weight/body weight ratio but more interestingly p21- deficient NEMOΔhepa livers showed more frequently small tumors in comparison to NEMOΔhepa livers.The protective role of p21 in carcinogenesis was the first time visible in 26 week old knockout animals. Here, the double knockout mice (NEMOΔhepa/p21−/− animals, meaning that the loss of p21 expression caused exacerbation of hepatocarcinogenesis. Analysing the livers of these mice revealed that only the number of nodules was increased, whereas the sizes of the tumors were not significantly enlarged. This suggests that the loss of p21 overexpression in NEMOΔhepa animals has more impact on tumor initiation than on tumor progression.Finally, a significantly increased number of HCCs were found in 52 week-old NEMOΔhepa/p21−/− animals display yellow inclusions and serum values for alkaline phosphatase, direct and total bilirubin confirmed the cholestatic phenotype. These cholestatic serum markers were significantly lower in NEMOΔhepa mice.Beside hepatocarcinogenesis p21 had an additional protective role in cholestasis. Livers of 52 week old NEMOΔhepa animals has a protective function in this model, as p21 protects against DNA damage, acceleration of hepatocarcinogenesis and cholestasis. Since liver disease progression is reduced in the presence of p21 expression, p21 has been shown to act as a tumor suppressor in the NEMOΔhepa model.Taken together, the enhanced p21 expression in NEMO


We have previously described a method that has the potential to improve surgery of arteriovenous malformations (AVMs). In the present paper, we present our clinical results.Of 78 patients referred for AVMs to our University Hospital from our geographical catchment region from 2005 through 2013, 31 patients were operated on with microsurgical technique. 3D MR angiography (MRA) with neuronavigation was used for planning. Navigated 3D ultrasound angiography (USA) was used to identify and clip feeders in the initial phase of the operation. None of our patients was embolized preoperatively as part of the surgical procedure. The niduses were extirpated based on the 3D USA. After extirpation, controls were done with 3D USA to verify that the AVMs were completely removed. The Spetzler three-tier classification of the patients was: A: 21, B: 6, C: 4. p = 0.019). We had no serious morbidity (GOS 3 or less). New deficits due to surgery were two patients with quadrantanopia (one class B and one class C), the latter (C) also acquired epilepsy. One patient (class A) acquired a hardly noticeable paresis in two fingers. One hundred percent angiographic cure was achieved in all patients, as evaluated by postoperative DSA.Sixty-eight feeders were identified on preoperative MRA and DSA and 67 feeders were identified and clipped by guidance of intraoperative 3D USA. Six feeders identified preoperatively were missed by 3D USA, while five preoperatively unknown feeders were found and clipped. The overall average bleeding was 440 ml. There was a significant reduction in average bleeding in the last 15 operations compared to the first 16 (340 vs. 559 ml,Navigated intraoperative 3D USA is a useful tool to identify and clip AVM feeders. Microsurgical extirpation assisted by navigated 3D USA is an effective and safe method for removing AVMs. The reported results from the various interventions for brain AVMs are heterogeneous . In spitNorway has a socialized and regionalized health care system where all patients with neurosurgical diseases in a defined geographical catchment region are referred to the serving university hospital. In the period from 2005 through 2013, 78 patients with AVMs were referred to our neurosurgical department. Before deciding the treatment, patients and their closest family were thoroughly informed about the different treatment modalities. Thirty-three patients with small AVMs in deep-seated locations were referred to Gamma Knife treatment. Thirty-one were treated with a microsurgical operation. Fourteen were not offered treatment because of high risk (S/M grade V), high age, and significant co-morbidity or due to patient preferences.The incidence of microsurgically operated AVMs in our region, with 700,000 inhabitants, is accordingly around 0.5 per 100,000 per year. The annual incidence rate of diagnosed AVMs is 1.2 per 100,000.All patients underwent both DSA and MRA as part of the diagnostic work up. Some of the patients with AVMs in eloquent areas also underwent fMRI and/or MR tractography. In all operations, we used navigated 3D USA, as described earlier . The RegThe preoperative 3D MRA was imported into the ultrasound-based intraoperative imaging system SonoWand . Power Doppler-based 3D USA was obtained during the procedure. Until 2009 we used version 1.4 of the SonoWand system as described in a previous paper . After tAs the first step during surgeries, the 3D MRA were imported into the navigation system and registered to the head of the patient. Based on the 3D MRA, the head was adjusted to facilitate a horizontal position of the craniotomy, which is associated with less brain shift during surgery and is better for obtaining good ultrasound 3D image recordings . The steIn the 31 patients, a total of 68 feeders were identified from preoperative DSA and 3D MRA. From 3D USA recordings, 67 feeders were also identified and subsequently clipped but not always the same feeders that had been identified on the preoperative images. A concordance between 3D MRA/DSA and 3D USA was found for 62 feeders (91 %). Six feeders identified in the preoperative MRA/DSA were missed by 3D USA. In one patient, as many as four very thin feeders were visualized in preoperative DSA/MRA that we were unable to identify in the 3D USA images. That patient had, at a previous occasion, been treated with embolization three times together with Gamma Knife treatment. On the other hand, 3D USA identified five feeders that were not seen in MRA/DSA, four of them in the 2nd 3D USA recorded after the initial clipping.After clipping of all the identified feeders, a new 3D USA recording showed in some cases large reduction of power Doppler signals in the nidus indicating low flow Figs.  and 6. I3D USA was also helpful in defining the borders of the AVM during extirpation. In cases where the power Doppler signal after clipping was reduced to nearly nothing in the nidus, the 3D USA acquired before the clipping of the feeders was used for accurate resection of the nidus Fig. .p = 0.019 by the Mann–Whitney U test). This may indicate some improvement during the development of the technology.The average peroperative bleeding for all cases was 440 ml. For the 10 class B and C cases, the average bleeding was 579 ml. For the first 16 patients, including 2 class B and 3 class C cases, the average bleeding was 559 ml, and in the last 15 cases including 4 class B and one class C, the average bleeding was 340 ml  two patients had acquired a homonym quadrantanopia as a consequence of the operation. One was a class B and the other was a class C patient. The latter also acquired epilepsy 2 months after the operation. One patient with a class A AVM in the precentral gyrus by the hand knob had no evident paresis after 3 months, but still he had a feeling of reduced fine motor control in two fingers. One patient with a class A AVM that had been treated with Gamma Knife radiosurgery 4 years earlier had no deficit 3 months after the operation, but 10 months after the operation she had an epileptic seizure. One patient with a large ICH at presentation had a hemiparesis that was temporarily worsened after the operation. At control 3 months later he was back to his preoperative status.All patients underwent DSAs 3 months after the operation. No residual AVM and normalization of the vasculature were confirmed in all cases.The technique of operating AVMs with early clipping of feeders based on neuronavigation was reported many years ago . HoweverIn a medium-sized neurosurgical unit, AVM operations are uncommon, with limited possibilities for neurosurgeons to obtain experience with these challenging patients. Therefore, every development that can make this operation easier should be acknowledged.One technique that has been used for some time in AVM surgery is indocyanine green angiography. We have no experience with this modality but according to a recent paper from one of the most merited groups in AVM surgery, it does not improve the clinical outcome and it seems to have shortcomings in deep AVMs .Our concept is somewhat different to the usual way of operating AVMs and can be summed up as follows: Navigated 3D MRA is registered to the patient’s head and rendered for planning of the craniotomy and where to clip the different feeding vessels. DSA is used in the preoperative work-up to confirm the 3D MRA findings of feeders and draining veins. The 3D USA can be recorded both before and after opening of the dura. The identification of the feeding vessels should be done based on the latter image volume, because there is often a small shift between navigated 3D USA acquired before and after opening of the dura. Before even touching the nidus, feeding vessels are identified, localized, and clipped. The identification of feeders based on 3D USA is reliable. Only six of 68 feeders identified on preoperative DSA/MRA were missed. Four of these feeders were in one patient that earlier had been treated three times with embolization and also have had Gamma Knife treatment. The feeders in this patient were tiny and hard to recognize also in the MRA volume. The strength of the method is that even very deep-seated feeders can be reached and identified with precise transcortical dissection by navigated 3D USA before starting the dissection of the nidus. Navigation towards the feeders is facilitated by navigated microscope. By moving the microscope to a position where the navigated centerline of the microscope hit the target point of the feeder, a precise dissection through the brain and identification of the feeder can be done by using the crosshairs of the microscope.When all the feeders have been clipped, a second 3D USA volume is acquired to recognize residual flow in the nidus and possibly unidentified feeders. This second 3D USA after clipping and before starting the resection was done routinely only in the last 15 cases. In four cases, additional feeding vessels not identified in the preoperative work-up were discovered and clipped. Presumably, the vessels were discovered because the major part of the flow was eliminated from the nidus.In most cases, the turgor and the power Doppler activity in the nidus was strongly reduced after clipping, but in a few cases, there was still cumbersome bleeding due to small feeders that could not be properly identified neither from the preoperative MR angiographies, DSAs, nor in the intraoperative 3D US angiograms. A navigated resection was done guided by the 3D USA volume of the nidus acquired before start of the clipping of feeders .Resection control with 3D USA after removal of the nidus was done in all cases to confirm complete removal of the AVM. No intraoperative or postoperative DSA was done until the DSA control 3 months after the surgery.One limitation of the technology is the lack of information about the direction of blood flow in the power Doppler angiography. A method has been developed for mapping angle-corrected velocities and flow direction to the 3D geometry of the vessels , 5, but The planning and clipping procedure added some extra time to the fist phase of the operation. The average operation time is 320 min for all operations and 274 min for the last 15 operations, which by some will be considered long. On the other hand, operation time was not an issue in this series, which also involved some other research tasks not reviewed in this paper.We did not use preoperative embolization for any of our patients. One of the patients had been unsuccessfully embolized years earlier at another hospital. Our assumption is that what can be gained with preoperative embolization in terms of making the extirpation of the nidus easier can be achieved by navigated intraoperative clipping of the feeding vessels without the extra risks associated with embolization. Moreover, incompletely embolized vessels may be a problem during subsequent surgery . There mIn only 25 % of our patients the AVMs were diagnosed because of hemorrhage. The way of handling unruptured AVMs is controversial. Studies have indicated that patients with unruptured AVMs can be handled with conservative, medical management instead of interventional therapy , 7. ThesIn a recent paper, serious procedural complications in AVM surgery were defined as GOS equal or less than 3 after 30 days [Considering neurological deficits, the only acquired deficit in the class A or low-grade AVM patients was one patient with an AVM in the precentral gyrus that had a feeling of reduced fine motor control of two fingers evaluated 3 months after the operation. It had no influence on his daily activity and can hardly be registered as morbidity. In a recent publication, a summation of the results of 12 published series showed a morbidity for low-grade AVMs of 2.2 % . The numThe effectiveness of the treatment is excellent since postoperative DSAs confirmed no residual AVM in any of the patients. The 100 % radiological cure is probably facilitated by active use of 3D US angiography during the operations.Navigated intraoperative 3D USA is a helpful tool to identify, localize, and clip AVM feeders. Good clinical and excellent radiological results can be obtained by microsurgical extirpation assisted by navigated intraoperative 3D US angiography.


Marko Kerac and Andrew Seal comment on the study by Langendorf and colleagues about the effectiveness of different strategies to prevent malnutrition in young children and discuss the implications of this study for food programs worldwide.Please see later in the article for the Editors' Summary PLOS Medicine:This Perspective discusses the following new study published in doi:10.1371/journal.pmed.1001714Langendorf C, Roederer T, de Pee S, Brown D, Doyon S, et al. (2014) Preventing Acute Malnutrition among Young Children in Crises: A Prospective Intervention Study in Niger. PLoS Med 11(9): e1001714. Céline Langendorf and colleagues conducted a pragmatic intervention study in Niger to assess whether distributions of supplementary foods in addition to household support by cash transfer effectively reduced malnutrition in children aged 6 to 23 months.PLOS Medicine exploring the effectiveness of different strategies to prevent malnutrition in young children is both timely and important Acute malnutrition (wasting and/or kwashiorkor) is a major global public health problem. Over 52 million children worldwide have wasting. 875,000 deaths per year in children aged 1–59 months are attributable to wasting; of those, 516,000 are attributable to severe wasting Langendorf and colleagues divided 48 rural villages in Niger into seven groups to test seven interventions The lowest incidences of acute malnutrition were found in the groups receiving both supplementary food and cash.The highest incidence of MAM was observed in the group receiving only cash, and the highest incidence of SAM was in a group receiving only supplementary food.Risks of malnutrition were significantly greater in several of the single-intervention groups versus the combined-intervention groups, whether the single intervention was cash or supplementary food for children.should be advocated. However, this paper has significantly raised the bar so that future arguments can be more scientific and focused on evidence rather than ideologies. For example, if managers of a different programme in a different setting believe that these results should not be generalised and that it is best for their programme to use either cash or food alone, that would be an entirely valid stance—but only if the case were made by carefully measuring and documenting outcomes so that they can be compared and contrasted with those presented by Langendorf and colleagues.Implementing any large-scale trial, let alone in an emergency setting, entails major practical, political, and other types of challenges. The achievements of the study team in successfully executing their project should be applauded. As well as being one of the first of its kind, the study has many methodological strengths, including rigorous and detailed reporting and analysis. However, there are also limitations. Whilst the number of individual children involved is impressive and the use of (some) randomization and control groups is notable, this is not a randomised controlled trial or even a cluster randomised trial. Each of the seven interventions were implemented only once in each of the seven study village groups. Follow-up duration was limited, and methodologically, the trial is more akin to an observational study: rather than proving the relative effectiveness of the various interventions, findings could equally be due to inter-site differences resulting in bias or unmeasured confounding. These limitations are acknowledged by the authors, who correctly argue that “some designs may not be possible despite their explanatory benefits.” This in no way diminishes the study's importance. Prior to this study, there were all kinds of reasons to justify cash-alone interventions, food-alone interventions, or both combined in particular contexts. All could be reasonably advocated. All still Numerous messages arise from this paper that will play a major role in informing and shaping future policy, practice, and research. First is that intervention “packages” tend to outperform single interventions. This observation fits with malnutrition having a complex and varied aetiology. As well as immediate causes such as illness or lack of food during a poor harvest, there may be numerous more distal underlying or contributory causes for malnutrition, such as household economic vulnerability and suboptimal caring practices. Rather than a diagnosis affecting just an individual child, malnutrition is arguably better viewed as a symptom of wider problems affecting the whole family. Unless these are recognised and addressed , real and sustained improvements are unlikely. Single interventions are limited not only because they might not address the core risk factor for a particular child, but because they might not be used as intended:Food packages can be carefully tailored to meet a child's nutritional requirements. However, such packages are liable to be shared  or sold so that families can get much-needed cash.Unconditional cash transfers have a unique capacity to be flexibly used so that each household can address its own particular needs, such as soap for hand washing, fuel for cooking, or food itself Combination packages help to mitigate such risks and increase the likelihood of benefit. Future work should thus explore how to optimise these packages. Clinical care for common childhood illnesses  should be considered, as that, too, may have added value. Costs are also vital to consider in future work. Though differing greatly in different settings, costs are critical when arguing for and developing a budget for any major intervention scale-ups. Greater clinical effectiveness in preventing malnutrition is always desirable, but it is cost-effectiveness that is key to long-term sustainability and appeal to funders who have to make tough decisions about spending limited budgets.Finally, this paper is a reminder that research can and should be done in challenging settings such as Niger. Global public health problems such as acute malnutrition must be tackled. The key results presented by Langendorf and colleagues all make great empirical sense. However, it is possible for plausible results from trials such as this one to be later contradicted by methodologically stronger studies


Mycobacterium marinum drug susceptibility testing (DST). As it is time-consuming, alternative methods, such as the E-test, were evaluated for M.marinum DST, but without success. The SLOMYCO Sensititre® panel, recently commercialized by TREK Diagnostic Systems , can be used for DST in slow-growing mycobacteria and for antimicrobial agents recommended by the Clinical and Laboratory Standards Institute (CLSI) for M.marinum DST. The main goal of this work was to evaluate the SLOMYCO Sensititre® panel method for DST in M.marinum isolates from human patients and fish relative to the reference agar dilution method.The agar dilution method is currently considered as the reference method for 2 dilution) was very good for both the agar dilution method and SLOMYCO Sensititre® panel (>90 % agreement). The percentage essential agreement between methods varied, depending on the drug: between 97 and 75 % for ciprofloxacin, moxifloxacin, linezolid, isoniazid, clarithromycin, amikacin, rifabutin and rifampin, 74 % for trimethoprim, 72 % for doxycycline, 70 % for sulfamethoxazole, 59 % for streptomycin, 33 % for ethambutol and only 2.2 % for ethionamide. When the agar dilution and SLOMYCO Sensititre® panel results were converted into interpretive criteria, the category agreement was 100 % for amikacin, ciprofloxacin, clarithromycin, moxifloxacin, rifabutin, sulfamethoxazole and trimethoprim, 98 % for ethambutol and 96 % for rifampin and no agreement for doxycycline.The reproducibility of the minimum inhibitory concentration (MIC) determination (±1 log® panel method could provide a potential alternative to the reference agar dilution method, when DST in M.marinum is required, except for doxycycline.The SLOMYCO Sensititre Mycobacterium marinum, a slow-growing nontuberculous photochromogenic mycobacteria, is an ubiquitous waterborne organism [M. marinum infection is commonly limited to the skin, but it can spread to deeper structures, resulting in tenosynovitis, arthritis and osteomyelitis [organism , 10, 17 organism , 10, 17.myelitis , 13 and,Mycobacterium marinum is naturally multi-drug resistant and there is no standardized antimicrobial treatment for M.marinum infections [M. marinum is well known [fections . As the ll known  and acqull known .M. marinum drug susceptibility testing (DST) [M.marinum [® panel was commercialized by TREK Diagnostic Systems  [M.marinum DST [The Clinical and Laboratory Standards Institute (CLSI) recommends microdilution for ng (DST) , but theng (DST) , 4, 19. .marinum , 11, 19.and, OH) . This isinum DST .® panel method for DST in M.marinum strains from humans and fish relative to the reference agar dilution method.The main goal of this work was to evaluate the SLOMYCO SensititreM. marinum isolates are described in Broutin et al. [M. marinum isolates from human patients and nine from fish were collected in France between 1995 and 2007. None was from patients who experienced treatment failure or relapse. M. marinum identification was performed using GenoType Mycobacterium AS/CM, a commercial multiplex line-probe assay . Isolates were stored at −80 °C in Middlebrook 7H9 broth  containing 5 % OADC  until determination of the Minimum inhibitory concentrations (MICs). Mycobacteria were then cultured in Löwenstein-Jensen (LJ) slants  and in Middlebrook 7H10 agar . The M. marinum ATCC 927 strain (from fish) and the M. marinum ATCC BAA-535/M strain isolated from an infected patient were used as controls for MIC determination.The origin and other information concerning the tested n et al. . The 35 Amikacin, ciprofloxacin, clarithromycin, doxycycline, ethambutol, ethionamide, isoniazid, rifampin, rifabutin, streptomycin and trimethoprim , linezolid  and moxifloxacin  were tested in this study. Stock solutions of each drug were prepared using the appropriate solvent and were filter-sterilized before storage at −80 °C. To prior testing, each drug was freshly diluted in sterile deionized water. The concentration ranges of the tested antimicrobial agents are indicated in Table 4 colony-forming units (CFU) per spot. Plates were incubated at 30 °C [M. marinum isolates/controls.The agar dilution method was performed on Müller-Hinton agar  supplemented with 5 % OADC according to CLSI . Twofoldat 30 °C . The MIC® panel were prepared according to the CLSI and the manufacturer’s instructions [2 incubator at 30 °C until the controls showed sufficient growth (7–14 days). The MICs were determined visually using an inverted mirror and read as the lowest concentration of the antibiotic showing 100 % growth inhibition.Inocula for the SLOMYCO Sensititreructions . SLOMYCOM. marinum ATCC 927 and ATCC BAA-535/M strains . Each test result was independently interpreted by two blinded readers. The reproducibility value was defined as the percentage of strains with the same MIC value ±1 log2 dilution at each test. The essential agreement between the agar dilution and SLOMYCO Sensititre® panel results was expressed as the percentage of isolates that showed the same MIC value ±1 log2 dilution with the two methods. Category agreement was evaluated using the breakpoints for determining the susceptibility and resistance categories recommended by CLSI [The reproducibility of both methods was evaluated by performing two independent tests for each method and for each of the 44 isolates  and five independent tests for the  by CLSI . For thi by CLSI .M.marinum isolates from infected humans and fish did not reveal any difference.The reproducibility of the results obtained with the agar dilution method (reference method) was very good Table  for all M.marinum strains (ATCC 927 and ATCC BAA-535/M) were within 0–1 dilution of the MICs of the 44 tested isolates and within the expected range.The MICs for the two reference 90) of amikacin (4 μg/mL), clarithromycin (2 μg/mL) and rifabutin (0.12 μg/mL) were below the CSLI breakpoint, whereas the MIC90 of ciprofloxacin (2 μg/mL), doxycycline (4 μg/mL), ethambutol (4 μg/mL), moxifloxacin (1 μg/mL), rifampin (1 μg/mL) and sulfamethoxazole (19 μg/mL) were close to the breakpoint [90 of rifampin, rifabutin, moxifloxacin and trimethoprim (between 0.1 and 1 μg/mL) were lower than those of the other tested antibiotics.The MICs at which 90 % of isolates were inhibited (MICeakpoint . The MIC90 of ethionamide (10 μg/mL), isoniazid (8 μg/mL) and streptomycin (16 μg/mL), for which breakpoints are not available, suggests that they are not good candidates for the treatment of M. marinum infection. In contrast, linezolid (MIC90: 2 μg/mL) was very effective against the different M. marinum isolates with MIC values among the lowest in our study.The relatively high MIC® panel method (tested method) produced remarkably consistent and reproducible results (Table 2 dilution) between the MICs obtained with the tested and the reference methods (Table ® panel method underestimated the MICs by 2–3 dilutions compared with the reference method. When the agar dilution and SLOMYCO Sensititre® panel results were converted into interpretive categories (resistance/susceptibility) using the CLSI breakpoints, the category agreement was 100 % for amikacin, ciprofloxacin, clarithromycin, moxifloxacin, rifabutin and sulfamethoxazole–trimethoprim (SMT-TMP), 98 % for ethambutol and 96 % for rifampin  was close to the susceptibility breakpoint obtained by using the agar dilution method (4 μg/mL).The SLOMYCO Sensititrets Table . Reproduts Table . The perds Table  greatly in Table . Two verM. marinum, but studies evaluating the concordance with the reference agar dilution method have not been published yet. As the SLOMYCO Sensititre® panel technique presents several advantages  recommend the SLOMYCO Sensititre® method for antibiotic susceptibility testing in tomation , 19 compM.marinum isolates from infected humans and fish could be explained by the fact that most of the clinical samples were from patients who handled infected fish (from aquarium tanks or fish-related work) and, therefore, the antibiotic susceptibility profiles of the human isolates reflected those of the fish isolates.The lack of difference between the MICs for the M. marinum isolates (from human and fish) was very good. All results of the independent tests were within the ±1 log2 dilution acceptable level of variation. Moreover, the level of agreement (±1 log2 dilution) between the results (MICs and interpretive categories) obtained with the SLOMYCO Sensititre® panel and the agar dilution methods was good for most of the antibiotics recommended by CLSI and ATS [M. marinum infections. It should be noted that two very major errors were observed for rifampin in isolates in which the MIC for rifampin was just above the breakpoint (2 μg/mL) and that still belong to the wild type population [M.marinum reported until now [Our results show that the reproducibility of the SLOMYCO Sensititre® results for the reference strains and the  and ATS  for the ntil now  was cleaConversely, poor agreement was observed for ethambutol. The MICs for ethambutol obtained with the SLOMYCO Sensititre® panel were 2–3 dilutions lower than those obtained with the reference method. However, this poor agreement resulted in only one very major error, when MICs were converted into interpretive categories. This discrepancy corresponds to a strain with a MIC just above the breakpoint 16 µg/mL)  infections include the use of streptomycin (for rifampin-resistant M. kansassii infection) and ethionamide  [M. marinum infections and the absence of breakpoints for NTM susceptibility and resistance to these two antibiotics did not allow predicting their potential efficiency in M. marinum infections [M. chelonae and M. marinum) [M. marinum, linezolid may be an interesting alternative therapeutic agent due to its pharmacological properties. This study confirmed that M. marinum is resistant to isoniazid and ethambutol [M. marinum susceptibility pattern corresponded to the wild type phenotype, as previously reported [90 was close to the breakpoint and clear evidence on the clinical efficacy of this antibiotic are lacking, it should not be recommended as a first-line drug for M.marinum infection treatment.In the case of doxycycline, no agreement was observed between methods resulting in 46 major errors. This could be explained by (i) the overestimation of doxycycline MICs by the SLOMYCO Sensititre® panel that could be due to the medium or pH, and (ii) the fact that the MIC studies , 15, 19.fection) , 12. Howfections . Linezolmarinum)  and for marinum) . In our hambutol  and the reported , 18, 19.® panel method for susceptibility testing in 44 M.marinum isolates (from humans and fish) relative to the reference agar dilution method. Our results indicate that the SLOMYCO Sensititre® panel method could provide a potential alternative to the reference agar dilution method, when DST in M.marinum is required, except for doxycycline. If doxycycline susceptibility needs to be tested, the use of another method (broth microdilution) is more appropriate.In this study, we evaluated the SLOMYCO SensititreWritten informed consent was obtained from the patients for the publication of this report.


To investigate the predictors of wasting, stunting and low mid-upper arm circumference among children aged 6–59 months in Somalia using data from household cross-sectional surveys from 2007 to 2010 in order to help inform better targeting of nutritional interventions.Cross-sectional nutritional assessment surveys using structured interviews were conducted among communities in Somalia each year from 2007 to 2010. A two-stage cluster sampling methodology was used to select children aged 6–59 months from households across three livelihood zones . Predictors of three anthropometric measures, weight-for-height (wasting), height-for-age (stunting) and mid-upper arm circumference, were analysed using Bayesian binomial regression, controlling for both spatial and temporal dependence in the data.The study was conducted in randomly sampled villages, representative of three livelihood zones in Somalia.Children between the ages of 6 and 59 months in Somalia.The estimated national prevalence of wasting, stunting and low mid-upper arm circumference in children aged 6–59 months was 21 %, 31 % and 36 %, respectively. Although fever, diarrhoea, sex and age of the child, household size and access to foods were significant predictors of malnutrition, the strongest association was observed between all three indicators of malnutrition and the enhanced vegetation index. A 1-unit increase in enhanced vegetation index was associated with a 38 %, 49 % and 59 % reduction in wasting, stunting and low mid-upper arm circumference, respectively.Infection and climatic variations are likely to be key drivers of malnutrition in Somalia. Better health data and close monitoring and forecasting of droughts may provide valuable information for nutritional intervention planning in Somalia. The burden of acute malnutrition is often greatest in areas suffering complex emergencies such as drought or conflict. Somalia has been without a nationally recognized central government since 1991 and is one of the most unsafe countries globally. This long period of insecurity and political instability has affected all facets of human life and development. Somalia is now ranked the fifth poorest country globally and has among the highest child and maternal mortality rates. It is also ranked lowest on the food security index and currently is estimated to have the highest rate of acute malnutrition in the world. In 2011, approximately 2·9 million Somalians, or 35 % of the population, experienced food crisis.Malnutrition is a leading cause of childhood deaths in low- and middle-income countries1 and . Interventions are often implemented under highly insecure conditions, especially in the southern parts of the country. Interventions against food insecurity and malnutrition have been a major focus, including out-patient therapeutic feeding programmes for severe acute malnutrition and targeted supplementary feeding programmes for moderately malnourished children under the age of 5 years and pregnant or lactating women.In the last two decades, international and local non-governmental organizations have supported essential public health services in Somalia. Primary health-care services are funded by several international organizations and donors, coordinated under the umbrella of the Somalia Support Secretariat, which was established under the auspices of a network including donors, UN agencies and international non-governmental organizations4. Int. Since 2011, the FSNAU has undertaken several random cluster nutritional surveys including demographic, household and anthropometric data. These surveys have been used to inform the nature and timing of nutritional interventions across the country and provide alerts for acute food insecurity. Data from these surveys provide an opportunity to identify the determinants of childhood malnutrition during the complex emergency situation in Somalia.In 1994 the World Food Programme set up the Food Security Analysis Unit, later renamed the Food Security and Nutritional Analysis Unit (FSNAU), to provide timely information to monitor and inform interventions to mitigate food insecurity and malnutrition in Somalia,9. S(–). Unravelling the determinants that are most important in this specific context can inform the efficient targeting of such interventions.Although inadequate nutritional intake is an obvious direct cause of malnutrition, many other factors are involved in causation, including poverty and access to health care, water and sanitation. These may be potential targets for interventions that could have a more sustained effect than reactive nutritional programmes–14. . Proximate factors have been the focus of most published literature and are child specific, including age, sex, inadequate nutritional intake and infections. Distal factors include features of the wider socio-cultural, economic, environmental, climatic and political context that affect household food security, personal security and access to economic opportunities, health care and education. These factors are likely to vary spatially and temporally, depending on geographic and climatic conditions and anthropogenic factors, and analyses must account for these variations.The determinants of childhood nutritional status can be classified as either proximate or distal15. PrIn the present study, the first nationwide investigation of the predictors of malnutrition among children aged 6–59 months in Somalia is undertaken using the data from the FSNAU household cross-sectional nutritional surveys done from 2007 to 2010. Bayesian spatial-temporal regression models are applied to the data to account for the space and time effects on wasting, stunting and mid-upper arm circumference (MUAC).. This group developed a nutrition strategy for the period 2011–2013 in response to persistently high rates of malnutrition in the country. So far, several nutrition initiatives have been rolled out including the out-patient therapeutic feeding programmes for the management of severe acute malnutrition implemented by UNICEF and other agencies and the targeted supplementary feeding programmes for the management of moderately malnourished under-5s and pregnant and lactating women supported by the World Food Programme. UNICEF currently targets 100 000 children aged 6–36 months with blanket distribution of ready-to-use food every two months in areas showing the highest malnutrition rates. The World Food Programme is also providing food assistance to vulnerable groups through institutional feeding and school feeding to about 90 000 beneficiaries. General food rations, consisting of cereals, corn–soya blend, sugar, fortified oil and iodized salt when available, are distributed to vulnerable rural populations, the urban poor and internally displaced persons. Despite these efforts, these interventions are thought to cover only a small proportion of the children under the age of 5 years who are likely to be malnourished in Somalia.In Somalia, a nutrition intervention group comprised of UNICEF, the World Food Programme and other government and non-governmental agencies was formed in 2006 to strengthen coordination of efforts against malnutrition,19. . Surveys were undertaken in all three zones of Somalia  and short (October to November) rainy seasons between 2007 and 2010. A stratified, multistage cluster sampling design was used where the sampling frame of a selected district was based on three livelihood definitions , within which thirty rural communities and thirty households within each community were selected at random20. Su Somalia .Fig. 1. Detailed descriptions of the survey methods and data collection are provided elsewhere. The spatial coordinates for each cluster were derived from several spatial databases.Sample sizes for the surveys (number of households and number of children) were calculated by Standardized Methodology for Survey in Relief and Transition (SMART) methods9. A l. A child was defined as wasted or stunted when his/her Z-score for weight-for-age or height-for-age, respectively, was below −2. Additionally, children with MUAC below 125 mm were classified as having ‘low MUAC’. These measures were treated separately during analysis.Anthropometric measures were used to compute wasting and stunting using WHO 2006 references23. A  and the UNICEF conceptual framework of child health and survival. The underlying predictors were related to household, maternal and environmental factors. At the child level, vitamin A supplementation in the last 6 months, diarrhoea, acute respiratory infection and incidence of febrile illness in the last 2 weeks before the survey, polio and measles vaccination history, sex and age of the child were examined in the present study. In addition, information was collected on child age, weight, height, MUAC and access to staple foods as well the mother’s age and MUAC. For each household, information recorded included the household size and age structure, sex of the household head and access to different types of foods in the last 24 h. Detailed description of the variables can be found in the online supplementary material (Table S1).The predictors for the present study were selected using both the WHO conceptual framework on childhood stunting24 and and food security on the indices of malnutrition were examined. These were rainfall, enhanced vegetation index (EVI), mean temperature, distance to water features and urbanization. Rainfall and mean temperature were derived from the monthly average grid surfaces obtained from the WorldClim database. The EVI values were derived from the MODerate-resolution Imaging Spectroradiometer (MODIS) sensor imagery for the period 2000–2010 while the urbanization information was obtained from the Global Rural Urban Mapping Project (GRUMP). All the environmental covariates were extracted from 1 km×1 km spatial resolution grids. Rainfall, temperature and EVI were summarized to compute seasonal averages using the four main seasons in Somalia: (i) December to March, the Jilal season, a harsh dry season; (ii) Gu which is the main rainy season from April to June; (iii) from July to September is the second dry season, the Hagaa; and (iv) the short rainy season known as Deyr from October to November. Further details of the covariates are provided in the online supplementary material .The effect of a set of five distal environmental covariates associated with vector-borne diseases25 andEthical approval was provided through permission by the Ministry of Health Somalia, Transitional Federal Government of Somalia Republic . Informed verbal consent was sought from all participating households and individuals..Three separate Bayesian hierarchical spatial-temporal regression models were used to analyse the predictors of stunting, wasting and MUAC among children under the age of 5 years. Model parameters were estimated using the Integrated Nested Laplace Approximation (INLA) algorithm for inference and was implemented in R project version 3·0·1 using R-INLA library30.Cluster-level effects were incorporated in the model to allow for the structured  and unstructured heterogeneity of malnutrition, using a convolution prior. District random effects were also included in this model. An assumption of additional flexibility in the model was made to allow for effects of non-linear predictors. Seasonality was controlled in the model as a factor with two unordered levels . A detailed description of the model procedures is provided in the online supplementary material .The results from the spatial-temporal Bayesian logistic regression are shown in Prior vitamin A supplementation in the 6 months before the survey was associated with less wasting and low MUAC, but had no significant effect on stunting. Access to staple sources of proteins within the 24 h prior to the survey was associated with less malnutrition as defined by all three indicators. Children who had consumed any of the staple sources of carbohydrates within the 24 h prior to the survey had lower risk of wasting and stunting. Access to fruits and vegetables was associated with a small increase in stunting. Larger household size and number of children under 5 years were associated with small increases in malnutrition. Higher MUAC of the mother was also associated with a small reduction in all three categories of malnutrition.Deyr (October to November short rains) to Gu (April to June long rains) was associated with lower risk of wasting and underweight, but no association with stunting.Of the selected environmental covariates, the intensity of vegetation cover was the predictor that showed the greatest association with the three indicators of malnutrition. A 1-unit increase in EVI was associated with a 38 %, 49 % and 59 % reduction in wasting, stunting and MUAC<125 mm, respectively. Change of season from  . A consistent association has been demonstrated between malnutrition and mortality from respiratory infections, where acute respiratory infection has been reported as a stronger predictor of malnutrition than diarrhoea. Some studies show that acute respiratory infection is associated with higher risk of malnutrition in children due to a lack nutrients from breast-feeding which are crucial for child growth.Diarrhoea during the previous 2 weeks was associated with increases of approximately 35 % in wasting, 29 % in stunting and 20 % in the chance of having MUAC<125 mm14. Th, but contrast with studies in Ethiopia, Nigeria and Ghana. Increase in the number of people in the household and in the number of children aged 6–59 months in a household were associated with high risk of malnutrition. This suggests that there is increased competition for household food in households with a high number of people.Compared with children aged <12 months, older children (12–<24 months and 24–59 months) had a lower chance of wasting and MUAC<125 mm. However, these children were more than twice as likely to be stunted. Girls were 27 % less likely to be wasted or stunted but 24 % more likely to have MUAC<125 mm compared with boys below the age of 5 years. These results are consistent with findings in some low-income settings in Africa which show a higher prevalence of stunting in male than in female children,35, . Given the large overall effect this index has on malnutrition and the susceptibility of Somalia to droughts, it is likely that its real relationship with malnutrition over the study period when a major drought occurred is underestimated.Interestingly, EVI, a proxy predictor of vegetation cover, was found to have the largest association with the three indices of malnutrition analysed in the present study. EVI is a satellite imagery-derived variable and characterizes the global range of vegetation state ranging from 0 (no vegetation cover) to 1 (high vegetation cover). Highly vegetated areas are a product of a combination of several variables including rainfall, seasonal and permanent water features, and to some extent underground water. In Somalia, it is an important correlate of availability of water for agriculture and pasture for livestock and may impact on household food security26. Gi. The large and significant associations of the malnutrition indicators in Somalia with the climatic indices such as EVI observed herein support this link. However, they also provide unique opportunities for using these climate indicators, which can be quantified at reasonable temporal and spatial resolutions, to forecast possible risks of malnutrition to support effective planning. This approach can then be validated through rapid and inexpensive household surveys and may provide a dynamic process to support readiness to respond to emerging nutritional threats in the country.Somalia, like most East and Horn of Africa countries, is prone to frequent droughts that often progress into famine, characterized by extreme food insecurity and malnutrition38. Th and in the current study the prevalences of fever and diarrhoea were relatively high and strongly associated with malnutrition. Regardless of the causal relationships, the majority of the available evidence on population health status in Somalia is likely to be suggestive and probably inadequate given the instability in the country and generally limited health research. Most available data are collected for programmatic purposes and are not necessarily hypothesis driven. Therefore, a stronger collaboration between non-governmental organizations and the regional research community should be fostered to help utilize existing programmatic infrastructure to collect health data through carefully designed studies that meet both operational and scientific needs. This will allow for a better analysis of the burden of ill health and risk factors in Somalia within the context of the ongoing instability.Somalia is regarded as a country with some of the worst indicators of health in the world6 and There are some limitations to the present study. Information on access to water and sanitation, which contributes to the prevalence of diarrhoea, was not collected in the FSNAU surveys used herein. Household income was collected only in the 2007 and 2008 surveys and thus excluded from the set of predictors. The effect of the prolonged political conflict in Somalia was also not accounted for in the study. As shown in the results, the data come largely from rural areas and while urban areas were seen to have overall lower rates of undernutrition, there may be pockets of high levels of undernutrition not captured in the study. In addition, the location and timing of intervention programmes that may have affected the nutritional status of children and seasonal migration of the pastoral communities in search for pasture were not controlled for in our study.The present study represents the first formal nationwide analysis of the predictors of malnutrition in Somalia. It identifies some important distal predictors of wasting, stunting and MUAC among children in Somalia. Predictors shown to be important were related to household size, access to food and environmental indicators of vegetation and temperature. Major nutritional intervention programmes by international humanitarian organizations in Somalia focus mainly on improving nutritional status at the child level through targeted feeding programmes. Despite this, malnutrition rates in Somalia remain at critical levels. In the present study we have shown that there are other important underlying factors at household and community levels that are associated with malnutrition in children and that require a wider response. Timely and targeted interventions at different seasons to mitigate the effects of rainfall variability, and hence vegetation and agriculture, should be investigated.