Ben Amor Research Articles

Nanotechnology's advancement in diabetes mellitus regenerative medicine.

Ben Amor, Ilhama,b; Chandran, Deepakc; Amin, Ruhule; Emran, Talha Bin PhDe,f, Author Information

Prevalence and Epidemiological Study of hepatitis B and C patients admitted to BEN AMOR DJILANI hospital in El Oued, Algeria

The Goal of the present study is to evaluate the epidemiological variations of hepatitis B and C in El Oued population. Our epidemiological study was carried out on 1798 hepatitis patients admitted to hospital BEN AMOR DJILANI the period (January 2013 to December 2020) in El Oued region. In Results, 5.45% of patients were aged less than 20 years 72.14% of the patients are aged between 20-40 years, 15.85% patients are ages between 40-60 years and 6.56 % patient are aged more than 60 years. In the other hand, 57.29% of hepatitis patients are men versus 42.71% are women. In this study, 95% of the patients had a hepatitis B whereas 5% of the people were affected by hepatitis C. Concerning regions of hepatitis patients, the eastern region include the highest number with 37%, followed by - with a small difference - the central region with 33%, then come the southern region with 18%, the northern region contain 11% and at least the western region which include the lowest number of hepatitis patients with 1%, of total cases of hepatitis patients in the state of El Oued. Hence epidemiological studies are needed to understand and improve facilities and implement effective treatment measures to control the disease and thus help to reduce mortality in the society associated with this disease.

Model protein excited states: MRCI calculations with large active spaces vs CC2 method.

Benchmarking calculations on excited states of models of phenylalanine protein chains are presented to assess the ability of alternative methods to the standard and most commonly used multiconfigurational wave function-based method, the complete active space self-consistent field (CASSCF), in recovering the non-dynamical correlation for systems that become not affordable by the CASSCF. The exploration of larger active spaces beyond the CASSCF limit is benchmarked through three strategies based on the reduction in the number of determinants: the restricted active space self-consistent field, the generalized active space self-consistent field (GASSCF), and the occupation-restricted multiple active space (ORMAS) schemes. The remaining dynamic correlation effects are then added by the complete active space second-order perturbation theory and by the multireference difference dedicated configuration interaction methods. In parallel, the approximate second-order coupled cluster (CC2), already proven to be successful for small building blocks of model proteins in one of our previous works [Ben Amor et al., J. Chem. Phys. 148, 184105 (2018)], is investigated to assess its performances for larger systems. Among the different alternative strategies to CASSCF, our results highlight the greatest efficiency of the GASSCF and ORMAS schemes in the systematic reduction of the configuration interaction expansion without loss of accuracy in both nature and excitation energies of both singlet ππ* and nπ* CO excited states with respect to the equivalent CASSCF calculations. Guidelines for an optimum applicability of this scheme to systems requiring active spaces beyond the complete active space limit are then proposed. Finally, the extension of the CC2 method to such large systems without loss of accuracy is demonstrated, highlighting the great potential of this method to treat accurately excited states, mainly single reference, of very large systems.

27-LB: Impact of the March–May 2020 Confinement on the Clinical-Biological Profiles of Diabetic Patients Hospitalized in Diabetology

Objective: In Tunisia, a total confinement was imposed from March 20 until May 4, 2020. The aim of our work was to assess the impact of this 2-month confinement on the clinical and biological profile of diabetic patients hospitalized in diabetology. Patients and Methods: This is a cross-sectional, observational, descriptive study that involved 110 diabetic patients hospitalized in department A of the National Institute of Nutrition and Food Technology of Tunis (Tunisia) from June 1 until June 30, 2020. Results : The mean age of the patients was 49.72±11.99years with ranges ranging from 16 to 77 years old; 63.6% of patients were female and 73.6% of patients were type 2. The average duration of diabetes was 11.53±8.62years, with extremes ranging from 0to24 years. The mean level of glycated hemoglobin was 12.03±3.97% and the Body-Mass-Index was 29.44kg/m² with extremes ranging from 16.26to40.19kg/m². Weight gain was reported in 73% of patients with an average of 4.77±1.98kg within 2 months of confinement, with extremes ranging from 2to11kg. Two patients (1.8%) were hospitalized for inaugural diabetic ketosis. The others were admitted for an imbalance(81.8%) or an acute decompensation of their diabetes(16.4%). The factors of imbalance or decompensation were: a poor compliance with hygienic-dietetic measures(90.9%); a medication poor compliance(41.8%), more than half of which(54.3%) was due to the inability of the patient to go to the local health center to obtain his medication; lipodystrophies(42.7% of patients on insulin); a stomatological infection(8.2%); an urinary tract infection(4.5%) and an acute coronary syndrome(0.9%). Conclusions : The diabetic patient is at high risk of a severe form of Covid-19. However, the confinement imposed by the pandemic seems to be one of the factors of diabetes imbalance (in particular by weight gain and poor adherence to therapy). It is therefore essential to strengthen the education and treatment of diabetic patients. Disclosure F. Mahjoub: None. N. Ben Amor: None. O. Berriche: None. H. Jamoussi: None.

Urgent needs to accelerate the race for COVID-19 therapeutics.

Urgent needs to accelerate the race for COVID-19 therapeutics.

Correcting COVID-19 vaccine misinformation: Lancet Commission on COVID-19 Vaccines and Therapeutics Task Force Members.

Correcting COVID-19 vaccine misinformation: Lancet Commission on COVID-19 Vaccines and Therapeutics Task Force Members.

The NMN Module Conducts Nodule Number Orchestra.

Legumes control nodule number through nodulation and autoregulation of nodulation (AON) pathways. Nodule Inception (NIN) is essential for rhizobial infection and nodule organogenesis in legumes. The GmNINa-miR172c-NNC1 (NMN) module, which consists of two positive regulators, GmNINa and miR172c, and a suppressor, NNC1, integrates both pathways. GmNINa activates miR172c to downregulate NNC1, leading to nodulation, while NNC1 inhibits miR172c expression, forming a negative feedback loop. GmNINa and NNC1 interact with each other and antagonistically fine-tune GmRIC1/RIC2 expression, turning AON on and off. Conversely, activation of AON inhibits GmNINa and miR172c expression, thereby reducing their inhibitory effects on NNC1 to attenuate both nodulation signaling and AON. The NMN module functions not only as an “accelerator” of the nodulation signal to promote nodulation but also as a “brake” on the signal by activating AON to orchestrate nodule number.

Commuting Double Sugeno Integrals

In decision problems involving two dimensions (like several agents in uncertainty) the properties of expected utility ensure that the result of a two-stepped procedure evaluation does not depend on the order with which the aggregations of local evaluations are performed (e.g., agents first, uncertainty next, or the converse). We say that the aggregations on each dimension commute. In a previous conference paper, Ben Amor, Essghaier and Fargier have shown that this property holds when using pessimistic possibilistic integrals on each dimension, or optimistic ones, while it fails when using a pessimistic possibilistic integral on one dimension and an optimistic one on the other. This paper studies and completely solves this problem when more general Sugeno integrals are used in place of possibilistic integrals, leading to double Sugeno integrals. The results show that there are capacities other than possibility and necessity measures that ensure commutation of Sugeno integrals. Moreover, the relationship between two-dimensional capacities and the commutation property for their projections is investigated.

The Use of Ultrasound for the Electrochemical Synthesis of Magnesium Ammonium Phosphate Hexahydrate (Struvite)

As concern increases over climate change, resource depletion, water, air and soil pollution, loss of biodiversity, the agricultural sector is under tremendous strain. Due to the exponential increase in global population, the world has seen a great rise in agricultural productivity1. With the clear global intensification of the agricultural sector, slurry management has now become a serious problem. Agricultural pollution is mainly due to the use of excess industrial fertilizers, nutrients and pesticides, and the presence of harmful bacteria, viruses and other micro-organisms induced by poor manure management in turns causing pollutants to enter soil and waterways (and airways too)1-4. Consequently, the sector has set some urgent priorities, for example by minimizing storage and encouraging the treatment of wastewater and solid slurries, by reducing energy consumption, and by creating on-site renewable energy systems1. Moreover, most of the agricultural manures contain useful nutrients such as nitrogen (N), phosphorus (P) and potassium (K), and efficiently extracting them to produce added-value products such as the slow-release fertilizer, magnesium ammonium phosphate hexahydrate (MgNH4PO4*6H2O) or struvite5, could reduce significantly environmental impacts and save on commercial fertilizers’ costs. Thus, it is important to implement novel, efficient and clean environmental and energy technologies with the view of recycling important nutrients from agricultural sludges and wastes. There are various methods to extract these important nutrients, such as chemical, biological and physical3,4. This present work highlights the recovery of these nutrients by electrochemical precipitation of struvite in the presence of ultrasound at various ultrasonic frequencies and intensities using magnesium (Mg) electrodes. It is shown that the combination of electrochemistry and ultrasound6 (20 kHz – 1 MHz), also known as sonoelectrochemistry 7-9, can facilitate and accelerate the production of struvite from “model” solutions, as long as the sonoelectrochemical reactor is optimised. Buckwell and E. Nadeu, Nutrient Recovery and Reuse (NRR) in European agriculture. A review of the issues, opportunities, and actions. RISE Foundation, Brussels, 2016.A. Sutton, C.M. Howard, J.W. Erisman, G. Billen, A. Bleeker, P. Grennfelt, H. van Grinsven, B. Grizzetti, (Eds.). The European Nitrogen Assessment. Cambridge University, Press Cambridge. 2011.M. Mehta, W.O. Khunjar, V. Nguyen, S. Tait and D.J. Batstone, Technologies to Recover Nutrients from Waste Streams: A Critical Review, Critical Reviews in Environmental Science and Technology, 45:4, 385-427, 2015.Huang, P. Zhang, Z. Zhang, J. Liu, J. Xiao and F. Gao, Simultaneous Removal of Ammonia Nitrogen and Recovery of Phosphate from Swine Wastewater by Struvite Electrochemical Precipitation and Recycling Technology, Journal of Cleaner Production, 127, 302-310, 2016.Moussa, G. Maurin, C. Gabrielli, and M. Ben Amor, Electrochemical Precipitation of Struvite, Electrochem. Solid-State Lett. 9(6), C97-C101, 2006.Yasui, Acoustic Cavitation and Bubble Dynamics, B.G. Pollet & M. Ashokkumar (Eds), SpringerBriefs, 10.1007/978-3-319- 68237-2, 2018.G. Pollet (Ed), Power ultrasound in electrochemistry: from versatile laboratory tool to engineering solution, John Wiley & Sons, Hoboken, NJ, USA (2012) ISBN: 978-0-470-97424-7.G. Pollet, A short introduction to Sonoelectrochemistry. Electrochem. Soc. Interface 2018, 27, 41–4.G. Pollet, M. Ashokkumar, Introduction to Ultrasound, Sonochemistry and Sonoelectrochemistry; B.G. Pollet, M. Ashokkumar (Eds); SpringerBriefs: Berlin, Germany, 2019; in press.

Solving sequential collective decision problems under qualitative uncertainty

This paper addresses the question of sequential collective decision making under qualitative uncertainty. It resumes the criteria introduced in previous works [4–6] by Ben Amor et al. and extends them to a more general context where every decision maker is free to have an optimistic or a pessimistic attitude w.r.t. uncertainty. These criteria are then considered for the optimization of possibilistic decision trees and an algorithmic study is performed for each of them. When the global utility does satisfy the monotonicity property, a classical possibilistic Dynamic Programming can be applied. Otherwise, two cases are possible: either the criterion is max oriented (the more is the satisfaction of any agent, the greater is the global satisfaction), and a dedicated algorithm can be proposed, that relies on as many calls to Dynamic Programming as the number of decision makers; or the criterion is min oriented (all the agents must like the common decision) and the optimal strategy can be provided by a Branch and Bound Algorithm. The paper concludes by an experimental study that shows the feasibility of the approaches, and details to what extent simple Dynamic programming algorithms can be used as approximation procedures for the non monotonic criteria.

Hospitalizations during a Month of Emergency in a Department of Diabetology

Introduction: Tunisia is not immune to the heavy expenses related to diabetes, especially the cost of hospitalization. The aims of the work were to evaluate the number of hospitalizations in a diabetes unit during an emergency month and to study the indications of these hospitalizations. Material and methods: Our work is a retrospective, descriptive study, performed in the department C of the National Institute of Nutrition and Food Technologies of Tunis. The patients included in our study had all consulted the dispatching of the Institute during October 2017 and carried the indication to emergency hospitalization. Results: The number of patients hospitalized was 90. The majority was female(72.2%). The mean duration of hospitalization was 5.3±2.8 days (from 3 to 21 days). The mean age was 39.8±4.7 years (from 16 to 81 years). The indications for hospitalization were as follows: acid-ketotic decompensation in 4.4%(n=4); ketotic decompensation in 14.4%; hyperosmolarity in 4.4%; diabetic foot in 5.6%; unstable diabetes in 7.8%; unbalanced diabetes in 22.2%; discovery of gestational diabetes in 21.1%; pregnancy and unbalanced diabetes mellitus in 16.7% and exploration of hypoglycaemia in a nondiabetic patient in 3.3%. The imbalance or decompensation factors for diabetes were lipodystrophy in 38.9%; drug and/or dietary non-compliance in 46.7%; an infection in 21.1%; insulin resistance in 16.7% and the absence of fast insulin bolus in 7.8%. As for hypoglycaemia in nondiabetics (n=3), two cases were confirmed and these were functional hypoglycaemias. The third case reversed was addressed in neurology and cardiology for exploration of discomforts. Conclusions: The main indication of emergency hospitalization was decompensated or unbalanced diabetes with lipodystrophies and poor adherence as the main causes. This underscores the importance of the repetition of education sessions for diabetic patients and the psychological care of them. Disclosure N. Ben Amor: None. F. Ben Mami: None.

Technology Focus: Formation Evaluation (August 2017)

Technology Focus Not too long ago, horizontal drilling revolutionized the petroleum industry. Emerging logging-while-drilling and geosteering technologies helped bring about multilateral, maximum-contact, and smart-completion wells, allowing reservoirs to be developed and produced much more efficiently and economically. This increased recovery, thus boosting reserves. In the process, formation evaluation plays a critical role in determining whether a producer or an injector is successful. More recently, efficient mass horizontal drilling and optimized multistage massive fracturing have turned traditionally nonreservoir source rock into sweet spots of energy strategy on a global scale. Production from unconventional reservoirs in the last decade has dramatically changed the petroleum industry, and this movement continues to evolve. Developing unconventional resources demands unconventional thinking, mainly because of the many challenges involved in evaluating tight source rocks. The two fundamental petrophysical properties, pore structure and wettability, are completely different between conventional reservoirs and unconventional source rocks. What may be next on the horizon? It is estimated that methane hydrates contain much more gas than shale plays, and, understandably, many countries are keen to explore this vast potential. As per recent news releases, China Geological Survey geoscientists and China National Petroleum Corporation engineers may have made a great technology breakthrough by being able to test significant hydrate-gas production in the South China Sea. If this is sustainable, exploring hydrate gas may be the next game changer for the energy industry. Evaluating hydrate gas formations would not be easy, however, and producing them safely, economically, and in an environmentally friendly way would be very challenging. But, I have high hopes that future technologies will be able to resolve these challenges to produce hydrate gas conventionally so it can be used to improve living standards. Recommended additional reading at OnePetro: www.onepetro.org. SPE 182448 The Petrophysics Role of Low-Resistivity Pay Zone of Talang Akar Formation, South Sumatera Basin, Indonesia by Z. Holis, SKK Migas, et al. SPE 183883 Using Digital Rock Modeling To Estimate Permeability and Capillary Pressure From NMR and Geochemical Logs by Hao Zhang, Baker Hughes, et al. SPE 183800 An Innovative Approach for Integrated Characterization and Modeling of a Complex Carbonate Reservoir by F. Ben Amor, Schlumberger, et al.

SIV Infection-Mediated Changes in Gastrointestinal Bacterial Microbiome and Virome Are Associated with Immunodeficiency and Prevented by Vaccination.

AIDS caused by simian immunodeficiency virus (SIV) infection is associated with gastrointestinal disease, systemic immune activation, and, in cross-sectional studies, changes in the enteric virome. Here we performed a longitudinal study of a vaccine cohort to define the natural history of changes in the fecal metagenome in SIV-infected monkeys. Matched rhesus macaques were either uninfected or intrarectally challenged with SIV, with a subset receiving the Ad26 vaccine, an adenovirus vector expressing the viral Env/Gag/Pol antigens. Progression of SIV infection to AIDS was associated with increased detection of potentially pathogenic viruses and bacterial enteropathogens. Specifically, adenoviruses were associated with an increased incidence of gastrointestinal disease and AIDS-related mortality. Viral and bacterial enteropathogens were largely absent from animals protected by the vaccine. These data suggest that the SIV-associated gastrointestinal disease is associated with the presence of both viral and bacterial enteropathogens and that protection against SIV infection by vaccination prevents enteropathogen emergence.

Dual Inequalities for Stabilized Column Generation Revisited

Column generation (CG) models have several advantages over compact formulations: they provide better linear program bounds, may eliminate symmetry, and can hide nonlinearities in their subproblems. However, users also encounter drawbacks in the form of slow convergence, also known as the tailing-off effect, and the oscillation of the dual variables. Among different alternatives for stabilizing the CG process, Ben Amor et al. [Ben Amor H, Desrosiers J, Valério de Carvalho JM (2006) Dual-optimal inequalities for stabilized column generation. Oper. Res. 54(3):454–463] suggest the use of dual-optimal inequalities (DOIs) in the context of cutting stock and bin packing problems. We generalize their results, provide new classes of (deep) DOIs, and show the applicability to other problems (vector packing, vertex coloring, bin packing with conflicts). We also suggest the dynamic addition of violated dual inequalities in a cutting-plane fashion and the use of dual inequalities that are not necessarily (deep) DOIs. In the latter case, a recovery procedure is needed to restore primal feasibility. Computational results proving the usefulness of the methods are presented.

Orthosymmetric bilinear map on Riesz spaces

Let $E$ be a Riesz space, $F$ a Hausdorff topological vector space (t.v.s.). We prove, under a certain separation condition, that any orthosymmetric bilinear map $T:E\times E\rightarrow F$ is automatically symmetric. This generalizes in certain way an earlier result by F. Ben Amor [On orthosymmetric bilinear maps, Positivity 14 (2010), 123--134]. As an application, we show that under a certain separation condition, any orthogonally additive homogeneous polynomial $P : E\rightarrow F$ is linearly represented. This fits in the type of results by Y. Benyamini, S. Lassalle and J.L.G. Llavona [Homogeneous orthogonally additive polynomials on Banach lattices, Bulletin of the London Mathematical Society 38 (2006), no. 3 459--469].

Letter to the editor concerning “hepatic myelopathy with spastic paraparesis: report of two cases and review of the literature” by S. Ben Amor et al. (Eur Spine J. 2013, Jun 1)

To the Editor, We read with great interest the article by Ben Amor et al. [1] published in the European Spine Journal entitled “Hepatic myelopathy with spastic paraparesis: report of two cases and review of the literature”. The authors state in their paper that there is no special diagnostic tool for hepatic myelopathy (HM), and that the diagnosis has to be established on clinical grounds after exclusion of other possible entities. However, in our opinion, there is a noticeable omission in this important article. Our previous study [2] revealed that motor evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) may be very helpful in the diagnosis of this rare complication of chronic liver diseases that is usually associated with a portosystemic shunt and likely to be overlooked. The authors demonstrated that central motor conduction studies by means of TMS are sensitive, accurate and easily applicable methods for detecting even a subclinical damage of the corticospinal tract. The threshold for corticospinal electrophysiological abnormalities was below that for clinical and/or radiological changes. Spinal cord involvement was evident even at the preclinical stage and became more overt as the disease progressed. Most of the examined patients did not have clinical symptoms and presented only physiological subclinical abnormalities. MEP studies may thus disclose an impairment of the corticospinal pathways even before HM is clinically manifest and enable an early diagnosis of HM. Since, liver transplantation (the first therapeutic option) should be performed before spinal cord damage becomes irreversible [3–5], the diagnosis of HM must be established as early as possible to enhance the chance of a complete recovery of the spinal cord. Therefore, we believe that such an important examination, which is at present widely and easily performed in the most neurophysiology laboratories, cannot be neglected. We found important to highlight that, especially in a review article on HM, this important diagnostic tool should be included and discussed.

CONTINUOUS GENERALIZED (θ, ϕ)-SEPARATING DERIVATIONS ON ARCHIMEDEAN ALMOST f-ALGEBRAS

Let A be an ℓ-algebra and let θ and ϕ be two endomorphisms of A. The couple (θ, ϕ) is called to be separating if xy = 0 implies θ(x)ϕ(y) = 0. If in addition θ and ϕ are ring endomorphisms of A, then the couple (θ, ϕ) is said to be ring-separating. An additive mapping δ : A → A is called (θ, ϕ)-separating derivation on A if there exists a (θ, ϕ)-separating couple with δ(xy) = δ(x)θ(y) + ϕ(x)δ(y), holds for all x, y ∈ A. If an addition θ, ϕ and δ are continuous, then δ is called a continuous (θ, ϕ)-ring-separating derivation. If in addition the couple (θ, ϕ) is ring-separating then δ is called a continuous (θ, ϕ)-ring-separating derivation. An additive mapping F : A → A is called a continuous generalized (θ, ϕ)-separating derivation on A if F is continuous mapping and if there exists a derivation d : A → A such that θ and ϕ are continuous, (θ, ϕ) is a separating couple and F(xy) = F(x)θ(y) + ϕ(x)d(y), holds for all x, y ∈ A. In this paper, we give a description of continuous (θ, ϕ)-ring-separating derivations on some ℓ-algebras. This generalizes a well-known theorem by Colville, Davis, and Keimel [Positive derivations on f-rings, J. Austral. Math. Soc23 (1977) 371–375] and generalizes the results of Boulabiar in [Positive derivations on almost f-rings, Order19 (2002) 385–395], Ben Amor [On orthosymmetric bilinear maps, Positivity14(1) (2010) 123–130] and Toumi et al. in [Order bounded derivations on Archimedean almost f-algebras, Positivity14(2) (2010) 239–245]. Moreover, inspiring from [Toumi, Order-bounded generalized derivations on Archimedean almost f-algebras, Commun. Algebra38(1) (2010) 154–164], it is shown that the notion of continuous generalized (θ, ϕ)-separating derivation on an archimedean almost f-algebra A is the concept of generalized θ-multiplier, that is an additive mapping satisfying F(xyz) = F(x)θ(yz), for all x, y, z ∈ A. In the case where A is an archimedean f-algebra, the situation improves. Indeed, the collection of all continuous generalized (θ, ϕ)-separating derivation on A coincides with the concept of θ-multiplier, that is an additive mapping satisfying F(xy) = F(x)θ(y), for all x, y ∈ A. If in addition A is a Dedekind complete vector lattice and θ is a positive mapping, then the set of all order bounded generalized of the form (θ, ϕ)-separating derivations on A, under composition, is an archimedean lattice-ordered algebra.

The Co-Management of Tuberculosis and Diabetes: Challenges and Opportunities in the Developing World

Yanis Ben Amor and Timothy Sullivan call for more research to examine whether the diagnosis and treatment of diabetes in TB patients may improve TB outcomes and patient survival.

STIM1 and STIM2 Are Located in the Acidic Ca2+ Stores and Associates with Orai1 upon Depletion of the Acidic Stores in Human Platelets

Mammalian cells accumulate Ca2+ into agonist-sensitive acidic organelles, vesicles that possess a vacuolar proton-ATPase. Acidic Ca2+ stores include secretory granules and lysosome-related organelles. Current evidence clearly indicates that acidic Ca2+ stores participate in cell signaling and function, including the activation of store-operated Ca2+ entry in human platelets upon depletion of the acidic stores, although the mechanism underlying the activation of store-operated Ca2+ entry controlled by the acidic stores remains unclear. STIM1 has been presented as the endoplasmic reticulum Ca2+ sensor, but its role sensing intraluminal Ca2+ concentration in the acidic stores has not been investigated. Here we report that STIM1 and STIM2 are expressed in the lysosome-related organelles and dense granules in human platelets isolated by immunomagnetic sorting. Depletion of the acidic Ca2+ stores using the specific vacuolar proton-ATPase inhibitor, bafilomycin A1, enhanced the association between STIM1 and STIM2 as well as between these proteins and the plasma membrane channel Orai1. Depletion of the acidic Ca2+ stores also induces time-dependent co-immunoprecipitation of STIM1 with the TRPC proteins hTRPC1 and hTRPC6, as well as between Orai1 and both TRPC proteins. In addition, bafilomycin A1 enhanced the association between STIM2 and SERCA3. These findings demonstrate the location of STIM1 and STIM2 in the acidic Ca2+ stores and their association with Ca2+ channels and ATPases upon acidic stores discharge.

<strong>Biodiversity of polychaetous annelids from the peninsula of Cap Bon, northeast coast of Tunisia</strong>

in Tunisia, polychaete studies are very rare (Fauvel 1924 a, b; Westheide 1972; Zibrowius 1970, 1971; Cantone 1978; Ben Amor 1984; Zaâbi & Afli 2005). The aim of this study was to update and fill in gaps in data of polychaetes of Tunisia. Samples were taken aboard the research vessel R/V Hannibal with a Van Veen grab (0.1 m²) and a core (0.009 m²). Nine sites located on the peninsula of Cap Bon on the NE coast of Tunisia, from Sidi Daoud to Ras Lahmer, were sampled in 2005 and 2006. A total of 5,920 individuals in 29 families and 88 species of polychaetes were identified. Twenty-nine species were newly recorded for Tunisia, including the ampharetid Isolda pulchella O.F. Müller, 1858 and the paraonid Aricidea cerrutii (Laubier, 1966). Diversity parameters were established. Abundance and species richness were higher in shallow waters dominated by Protodorvillea kefersteini (McIntosh, 1869) and Malacoceros fuliginosus (Claparède, 1868) than in deep waters where Aponuphis fauveli (Rioja, 1918) and Euclymene palermitana (Grube, 1840) dominated. Multivariate methods, including the Shannon diversity index, cluster analysis, and rank frequency analysis, were used to characterize the spatial structure and temporal variability of the different communities.