Harsh Desert Conditions Research Articles

Biodiversity in Thar Desert and its Role in Sustainable Agriculture

The country has both hot and cold deserts. The Thar Desert, seventh largest desert in the world, harbors several species that have adapted themselves to survive in the harsh desert conditions. The floral diversity includes 682 species (63 introduced species), belonging to 352 genera and 87 families. The degree of endemism of plant species in the Thar Desert is 6.4 percent, which is relatively higher than the degree of endemism in the world famous Sahara desert. The faunal diversity represents 755 invertebrate and 440 vertebrate species, including 140 bird and 41 mammalian species and the only known population of the Asiatic wild ass. It is highlighted that sustainable use and management of this biodiversity is necessary to support human and livestock needs besides conservation. The strategy should be such that it is supported by public.

<p><strong><em>Euphorbia rimireptans</em></strong><strong> (Euphorbiaceae, Articulofruticosae), a new species from the Skeleton Coast, Namibia</strong></p>

Euphorbia rimireptans, here described as a new species, is known only from the northern part of the Skeleton Coast (part of the Namib Desert) in the Kaokoveld Centre of Endemism, northwestern Namibia. These perennial shrublets grow on rocky outcrops of latite under harsh desert conditions. Diagnostic characters for E. rimireptans include the procumbent, sometimes pendant habit, the soft, rubber-like terete or slightly tapering branches that are curved or ± straight, frequently orientated in the same direction from the base, and the glabrous or sparsely hairy capsule, which releases verrucose ovoid seeds. A comparison of some of the more prominent morphological features to differentiate between E. rimireptans and its possible nearest relative, E. giessii, is provided.

Aircraft turbines time-to-failures process modeling using RBF NN

PurposeThe purpose of this paper is to formulate a specialized artificial neural network algorithm utilizing radial basis function (RBF) for modeling of time to failure of aircraft engine turbines.Design/methodology/approachThe model uses training failure data collected from operators of turboprop aircraft working in harsh desert conditions where sand erosion is a detrimental factor in reducing turbine life. Accordingly, the model is more suited to accurate prediction of life of critical components of such engines. The used RBF employs a closest neighbor type of classifier and the hidden unit’s activation is based on the displacement between the early prototype and the input vector.FindingsThe results of the algorithm are compared to earlier work utilizing Weibull regression modeling, as well as Feed Forward Back Propagation NN. The results show that the failure rates estimated by RBF more closely match actual failure data than the estimations by both other models. The trained model showed reasonable accuracy in predicting future failure events. Moreover, the technique is shown to have comparatively higher efficiency even with reduced number of neurons in each layer of ANN. This significantly decreases computation time with minimum effect on the accuracy of results.Originality/valueUsing RBF technique significantly decreases the computational time with minimum effect on the accuracy of results.

Modelowanie uszkodzeń elementów silnika samolotowego w oparciu o sztuczne sieci neuronowe o radialnych funkcjach bazowych

The objective of this research is to present a model to predict failure of two categories of critical aircraft engine components; nonrotating components such as valves and gearboxes, and rotating components such as engine turbines. The work utilizes Weibull regression and artificial neural networks employing Back Propagation (BP) as well as Radial Basis Functions (RBF). The model utilizes training failure data collected from operators of turboprop aircraft working in harsh desert conditions, where sand erosion is a detrimental factor in reducing turbine life. Accordingly, the model is more suited for accurate prediction of life of critical components of such engines. The algorithm, which uses Radial Basis Function (RBF) NN, uses a closest point specifier. The activation is based on the deviation of the earlier prototype from the input vector. Two earlier models are used for comparison purposes; namely Weibull regression modeling and Feed-Forward BP network. Comparison results show that the failure times represented by RBF are in better compromise with actual failure data than both earlier modeling methods. Moreover, the technique has comparatively higher efficiency as the neuron’s number in each layer of ANN is reduced, to decrease computation time, with minimum effect on the accuracy of results.

Thermal modeling and optimization of microalgal biomass production in the harsh desert conditions of State of Qatar

Microalgal culture in solar conditions raises several challenges, especially in the harsh desert areas of the Middle East where microalgal culture is a valuable candidate for biomass production on non-arable land.Here we investigate issues related to the temperature regimes involved in open culture systems used to cultivate microalgae in the State of Qatar. A generic thermal modeling approach is presented. The model produced takes into account all relevant heat exchanges involved in the process, including solar radiation absorption, water evaporation and convection with ambient air, and is proved valid for accurate prediction of temperature regimes.The model is then used to analyze heat exchanges and thermal behavior of the process for both summer and winter periods. Temperature regimes are then compared to the requirements of a heat-resistant and a temperate-climate microalgal strain. Finally, various simulations are run to identify how to set an optimized yearly microalgal culture in harsh desert conditions.

Estrous Cycle of Induced Ovulators: Lesson From The Camel — A Review

Camel, rabbit, cat, ferrets, minks, koala and meadow moles are induced ovulators requiring copulation to trigger the ovulatory process and the estrous cycle differs from that of other domestic animals. The estrous cycle in these animals composed of follicular recruitment, follicular growth, follicular maturity and follicular regression phase. These animals are variously reared as companion, fur-bearing and meat animals. Among these, the camel is the most valuable and classical induced ovulator which is rear not only for milk and meat, but as work animal and contributes effectively to the welfare of people in harsh and difficult environments. As a classical induced ovulatory, camelid has cycling receptivity with distinctive estrus but requires mating in order to ovulate. The other classes of induced ovulators like cats and ferrets require both the presence of male to achieve behavioral estrus and actual copulation to ovulate. The camel has good prospects of survival as a suitable livestock for projects of sustainable agriculture and animal production under harsh desert or arid conditions. However the reproductive nature of camels presents a huge challenge to camel husbandry. The natural constraints include the long period of attaining puberty, limited breeding season, difficulties in induced ovulation, long gestation period and inter-calving intervals. Efforts to improve the reproductive efficiency of the female camel are closely related to a better understanding of the folliculogenesis or follicular wave pattern. Many investigators might not be aware of the peculiar reproductive information available about this animal species. A working knowledge of ovarian function or estrous cycle will be of immense importance to the application of assisted reproductive technologies (ARTs) and enhancements of reproduction in camelids. This work presents the overview of estrous cycle in camel as a classical example of induced ovulators with the aim of providing current knowledge to the reader and to stimulate wider research interest in camel research and reproduction.

Irradiance, thermal and electrical coupled modeling of photovoltaic panels with long-term simulation periods under service in harsh desert conditions

Predicting the electrical yield of photovoltaic (PV) devices over long periods of operating conditions is essential for the cost assessment of projects. The presented modeling of a PV panel couples different physics using finite-element method, focusing on long-term operations under desert conditions. The coupled physics are: (i) the solar irradiance; (ii) the heat transfer within the module, influencing the temperature-dependent conversion efficiency; and (iii) its electrical yield. The thermal behavior of a PV panel and predictions of its electrical yield are investigated for several years of atmospheric conditions in Saudi Arabia, with elementary assumptions regarding the performance of the selected PV device.

Spatial information recovery in the desert using LMS-based geodetic network adjustment

This paper describes the local coordinate system recovery at the archaeological site Tell el-Retaba (Egypt), without any GNSS technology or the positioning in an official reference frame available. Completely destroyed control points were restored using geodetic network adjustment based on terrestrial observations and multi-epoch solution of the Least Mean Square models, and transformed into the original local coordinate system using identical points located on ancient mud-brick structures in former trenches. However, current and past measurements of excavated objects fit almost perfectly. Statistical and empirical tests indicate that the outliers correspond with measurements in harsh desert conditions.

Genomic Analysis and Comparison of Pakistani Camels (Camelus dromedarius) by Prion Gene

Background: In many parts of the Old World, domesticated camels (genus - Camelus) are an essential resource, providing food, labor, commodities, and sport to millions of people Of the three extent species, two have been domesticated (singlehumped dromedarius, Camelus dromedarius, and two humped Bactrian camels Camelus bactrianus) and one remains wild (two-humped wild Bactrian camels Camelus ferus). All three species possess a variety adaptations to harsh desert conditions, including mechanisms to tolerate of extreme temperatures, dehydration, and sandy terrain. People residing in harsh climate zones of the world are being benefitted by raising camels in terms of draft, milk, meat, hides and wool from centuries. There are different breeds of dromedary camels distributed in various parts of Pakistan; however there have been scarcity of research work on camels in Pakistan. Identification of novel link between Camel breeders with fatal neurodegenerative disorders is presence or not can be detect by a Prion gene and it was not carried out in Pakistan soil to date. Prion diseases which are a group of fatal neurodegenerative disorders affect both animals and humans. It is believed that the prions are infectious agents responsible for transmissible spongiform encephalopathies. In this study we report the first study on Prion protein gene in dromedary camels of Pakistan.Material, Methods & Results: Genes are the blueprint of life and determine the functional aspects of cellular mechanisms. Genomic DNA of the enrolled blood samples was extracted using the Nucleospin® DNA extraction kit. Genomic DNA was run on Agarose gel electrophoresis, checked the Genomic DNA quality and amplified using prion region specific primer pair. Prion protein gene was amplified (770 bp) in 35 individuals of seven dromedary camel breeds from the province Balochistan and Punjab of Pakistan. Samples having required fragment size were selected and sent for sequencing through Sanger Sequencing. All the sequences were aligned through multiple sequence alignment and edited using Codon Code aligner and explored for phylogenetic analysis. A portion of 667 bp was finally selected for phylogenetic analysis of dromedary camels from Pakistan with 61 different mammalian species (drawn from GenBank) that revealed five different clades. We found 99.9% nucleotide sequence similarities among Dromedary camels (Germany), Dromedary camels (Iran), and Dromedary camels (Pakistan). We observed deletion in dromedary camels in codon region 66-69 except wild Bactrian camels that might be the causative factor for Prion protein gene resistance in camels. The Neighbor-Joining method with bootstrap analysis of 1000 replicates was used to draw phylogenetic tree.Discussion: This study documents the presence of 14 PrP polymorphisms and shows the relationship between different camel breeds. The deletion had not previously been examined PrP allelic variation, and was found to segregate in these breeds. However, additional data are necessary to demonstrate PrP and genetic approach will be ideal for the future studies and, more investigations are necessary to demonstrate PrP genetic resistance in camels. The utility of these techniques in identifying Prion genes and selecting superior animals and culling the weak animals and making them parents of the next generation that will lead to producing more meat and milk with fewer animals are well discussed and by slaughtering of high Prion incidence will eliminate human animal fatal neurodegenerative disorders.

Perennials but not slope aspect affect the diversity of soil bacterial communities in the northern Negev Desert, Israel

Underneath the canopy of perennials in arid regions, moderate soil temperature and evaporation, as well as plant litter create islands of higher fertility in the low-productivity landscape, known as ‘resource islands’. The sparse distribution of these resource islands is mirrored by soil microbial communities, which mediate a large number of biogeochemical transformations underneath the plants. We explored the link between the bacterial community composition and two prevalent desert shrubs, Zygophyllum dumosum and Artemisia herba-alba, on northern- and southern-facing slopes in the northern highlands of the Negev Desert (Israel), at the end of a drought winter mild rainy season. We sequenced the bacterial community and analysed the physicochemical properties of the soil under the shrub canopies and from barren soil in replicate slopes. The soil bacterial diversity was independent of slope aspect, but differed according to shrub presence or type. Links between soil bacterial community composition and their associated desert shrubs were found, enabling us to link bacterial diversity with shrub type or barren soils. Our results suggest that plants and their associated bacterial communities are connected to survival and persistence under the harsh desert conditions.

Complete mitochondrial genome of Anxi cattle (Bos taurus)

Anxi cattle (Bos taurus) is an endangered species native to China. It has strong adaptive abilities to harsh desert conditions such as heat, cold, and drought tolerance; disease resistance; and stable inheritance. However, it is on the brink of extinction because of its shrinking population in the past few years due to the introduction and invasion of exotic species and the lack of awareness of germplasm resource protection. Mitochondrial DNA, a well-known genetic marker, has been successfully applied to molecular phylogenetics and population genetics. This study reported a whole mitogenome for Anxi cattle (B. taurus), which was sequenced using Illumina Hiseq 2500 platform. The length of complete mitogenome of Anxi cattle (B. taurus) breed was 16,341 bp (bp), containing 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a non-coding control region. It also contained the origin of L-strand replication (32 bp long), which was between tRNA-Asn and tRNA-Cys. The base composition of the genome was A (33.4%), C (26.0%), G (13.4%), and T (27.2%) with an A + T content of 60.6%. The molecular phylogenetic analysis revealed four major lineages, and the Anxi cattle breed had a close genetic connection with B. taurus and B. indicus clusters but was still distinctly outside them. This study identified the phylogenetic status of Anxi cattle (B. taurus) breed and offered essential molecular genetic information for the conservation of germplasm resources.

Effect of Sandblasting on Tensile Properties, Hardness and Fracture Resistance of a Line Pipe Steel Used in Algeria for Oil Transport

Transport of oil and gas through pipelines in the harsh conditions of the Algerian desert, results in erosion of the pipeline materials. Erosion is a mechanical process that causes a loss of wall thickness, damage and residual stresses on the surface of a pipe due to shocks between sand particles and structure surface. Damage manifests by spalling craters of different shapes and depths. The evaluation of tensile properties and hardness after sandblasting for different durations has been performed on API 5L X70 pipeline steel. Particular attention has been paid to fracture resistance after sandblasting to provide the necessary data for defect assessment, specially the effect of sandblasting on the Material Failure Master Curve (MFMC). The results demonstrated that the sandblasting has slightly increased the yield stress, the ultimate strength and the fracture toughness and, at the same time, had an adverse effect on elongation, young’s modulus, hardness and thickness of the tested pipeline.

Transcriptomic analysis of salt stress responsive genes in Rhazya stricta.

Rhazya stricta is an evergreen shrub that is widely distributed across Western and South Asia, and like many other members of the Apocynaceae produces monoterpene indole alkaloids that have anti-cancer properties. This species is adapted to very harsh desert conditions making it an excellent system for studying tolerance to high temperatures and salinity. RNA-Seq analysis was performed on R. stricta exposed to severe salt stress (500 mM NaCl) across four time intervals (0, 2, 12 and 24 h) to examine mechanisms of salt tolerance. A large number of transcripts including genes encoding tetrapyrroles and pentatricopeptide repeat (PPR) proteins were regulated only after 12 h of stress of seedlings grown in controlled greenhouse conditions. Mechanisms of salt tolerance in R. stricta may involve the upregulation of genes encoding chaperone protein Dnaj6, UDP-glucosyl transferase 85a2, protein transparent testa 12 and respiratory burst oxidase homolog protein b. Many of the highly-expressed genes act on protecting protein folding during salt stress and the production of flavonoids, key secondary metabolites in stress tolerance. Other regulated genes encode enzymes in the porphyrin and chlorophyll metabolic pathway with important roles during plant growth, photosynthesis, hormone signaling and abiotic responses. Heme biosynthesis in R. stricta leaves might add to the level of salt stress tolerance by maintaining appropriate levels of photosynthesis and normal plant growth as well as by the participation in reactive oxygen species (ROS) production under stress. We speculate that the high expression levels of PPR genes may be dependent on expression levels of their targeted editing genes. Although the results of PPR gene family indicated regulation of a large number of transcripts under salt stress, PPR actions were independent of the salt stress because their RNA editing patterns were unchanged.

Anastatica hierochuntica, an Arabidopsis Desert Relative, Is Tolerant to Multiple Abiotic Stresses and Exhibits Species-Specific and Common Stress Tolerance Strategies with Its Halophytic Relative, Eutrema (Thellungiella) salsugineum.

The search for novel stress tolerance determinants has led to increasing interest in plants native to extreme environments – so called “extremophytes.” One successful strategy has been comparative studies between Arabidopsis thaliana and extremophyte Brassicaceae relatives such as the halophyte Eutrema salsugineum located in areas including cold, salty coastal regions of China. Here, we investigate stress tolerance in the desert species, Anastatica hierochuntica (True Rose of Jericho), a member of the poorly investigated lineage III Brassicaceae. We show that A. hierochuntica has a genome approximately 4.5-fold larger than Arabidopsis, divided into 22 diploid chromosomes, and demonstrate that A. hierochuntica exhibits tolerance to heat, low N and salt stresses that are characteristic of its habitat. Taking salt tolerance as a case study, we show that A. hierochuntica shares common salt tolerance mechanisms with E. salsugineum such as tight control of shoot Na+ accumulation and resilient photochemistry features. Furthermore, metabolic profiling of E. salsugineum and A. hierochuntica shoots demonstrates that the extremophytes exhibit both species-specific and common metabolic strategies to cope with salt stress including constitutive up-regulation (under control and salt stress conditions) of ascorbate and dehydroascorbate, two metabolites involved in ROS scavenging. Accordingly, A. hierochuntica displays tolerance to methyl viologen-induced oxidative stress suggesting that a highly active antioxidant system is essential to cope with multiple abiotic stresses. We suggest that A. hierochuntica presents an excellent extremophyte Arabidopsis relative model system for understanding plant survival in harsh desert conditions.

Diversity and ecology of rotifers in sadul branch of sirhind feeder, Hanumangarh (Rajasthan)

The Thar Desert is a desolated vast sandy stretch of inhospitable landscape. The ecology of this desert is characterized by harsh climatic conditions. For harnessing the harsh desert conditions, water is the most important component. To overcome adverse climatic conditions, the Sirhind Feeder was conceived in this region. Rotifers are one of the most important constituents of zooplankton community in fresh water ecosystem. These minute and delicate animals comprise an integral part in the aquatic food chain. Rotifers are hardy enough to tolerate extreme environmental conditions, features that place them in the class of best bioindicators of water quality. Present study was made to explore the diversity, density and ecology of rotifer fauna in sadul branch of Sirhind Feeder in Hanumangarh (29o5' to 30o6' north latitude and 74o3' to 75o3' east longitudes). The observations were made for a period of six months (January 2014 to June 2014). Physico-chemical conditions revealed that canal was shallow with turbid, well oxygenated, alkaline, hard and saline water. The study revealed the occurrence of seven species of rotifers represented by Keratella vulga, Keratella cochlearis, Brachionus bidentata, Brachionus calyciflorus, Filinia longiseta, Monostyla lunaris and Monostyla quadridentata. Rotifers were noted as peak population during the month of April (290 No./l).

Isolation and Characterization of the Native Rhizobia Under Hyper-Salt Edaphic Conditions in Ouargla (southeast Algeria)

The bacteria of the soil usually called rhizobium have a considerable importance in agriculture because of their capacity to fix the atmospheric nitrogen in symbiosis with the plants of the family of legumes. The present work was study the effect of the salinity on growth and nodulation of alfalfa-rhizobia symbiosis at different agricultural experimental sites in Ouargla. The experiment was conducted in 3 steps which we were made. The first one was the isolation and characterization of the Rhizobia, next the evolution of the isolates tolerance to salinity at three levels of NaCl (6, 8,12 and 16g/L), and the last step was the evolution the tolerance on symbiotic characteristics. The results showed that the phenotypic characterizations behave practically as Rhizobia spp, and the effects of salinity affect the symbiotic process. The tolerance to high levels of salinity and the survival and persistence in severe and harsh desert conditions make these rhizobia highly valuable inoculums to improve productivity of the leguminous plants cultivated under extreme environments.

Reproductive biology of the horned viper, Cerastes cerastes gasperettii in the central region of Saudi Arabia

The reproductive biology of the horned viper, Cerastes cerastes gasperettii, in Riyadh region of Saudi Arabia was investigated over a period of one year. Study of reproductive cycle of male and female C. c. gasperettii revealed that the breeding season is relatively short (April and May). Thereafter females laid eggs by mid of July and hatching probably had taken place by the end of September. No activity was observed during winter, this may indicate just a single clutch per year. Relative testis weight to body weight was drastically increased (X¯=0.88%) during the peak of reproductive activity (May) where maximal expansion of seminiferous tubules was also attained during April and May (X¯=209μm and 191μm, respectively). Likewise, the ovarian activity was the highest during May where ovarian parameters were greater in terms of relative ovarian weight to body weight and ova diameter being 0.46% and 2.29mm, respectively. Fat body weight was increased drastically just before the peak of reproductive activity then started to decline during June. It could be concluded that the harsh desert conditions and similar environments certainly affect reproductive activity of Saudi Arabian reptiles including snakes.

Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes.

The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw toward fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus) with longer isolation age. During the initial melt there was a mean nine times enrichment in dissolved chloride relative to mean concentrations of the initial frozen holes indicative of an ionic pulse, with similar mean nine times enrichments in nitrite, ammonium, and dissolved organic matter. Nitrate was enriched twelve times and dissolved organic nitrogen six times, suggesting net nitrification, while lower enrichments for dissolved organic phosphorus and phosphate were consistent with net microbial phosphorus uptake. Rates of bacterial production were significantly elevated during the ionic pulse, likely due to the increased nutrient availability. There was no concomitant increase in photosynthesis rates, with a net depletion of dissolved inorganic carbon suggesting inorganic carbon limitation. Potential nitrogen fixation was detected in fully melted holes where it could be an important source of nitrogen to support microbial growth, but not during the ionic pulse where nitrogen availability was higher. This study demonstrates that ionic pulses significantly alter the timing and magnitude of microbial activity within entombed cryoconite holes, and adds credence to hypotheses that ionic enrichments during freeze-thaw can elevate rates of microbial growth and activity in other icy habitats, such as ice veins and subglacial regelation zones.

Functional genomic and phenotypic responses to desiccation in natural populations of a desert drosophilid.

We used whole-transcriptome microarrays to assess changes in gene expression and monitored mortality rates and epicuticular hydrocarbons (CHCs) in response to desiccation stress in four natural populations of Drosophila mojavensis from Baja California and mainland Mexico. Desiccation had the greatest effect on gene expression, followed by biogeographical variation at regional and population levels. Genes involved in environmental sensing and cuticular structure were up-regulated in dry conditions, while genes involved in transcription itself were down-regulated. Flies from Baja California had higher expression of reproductive and mitochondrial genes, suggesting that these populations have greater fecundity and higher metabolic rates. Host plant differences had a surprisingly minor effect on the transcriptome. In most cases, desiccation-caused mortality was greater in flies reared on fermenting cactus tissues than that on laboratory media. Water content of adult females and males was significantly different and was lower in Baja California males. Different groups of CHCs simultaneously increased and decreased in amounts due to desiccation exposure of 9 and 18 h and were population-specific and dependent on larval rearing substrates. Overall, we observed that changes in gene expression involved a coordinated response of behavioural, cuticular and metabolic genes. Together with differential expression of cuticular hydrocarbons, this study revealed some of the mechanisms that have allowed D. mojavensis to exploit its harsh desert conditions. Certainly, for D. mojavensis that uses different host plants, population-level understanding of responses to stressors associated with future climate change in desert regions must be evaluated across geographical and local ecological scales.

Isolation and characterization of salt-tolerant rhizobia native to the desert<br>soils of United Arab Emirates

The salinity tolerance of naturally occurring rhizobia, isolated from the root nodules of three leguminous plants, namely sesbania (Sesbania sesban), lablab (Lablab purpureus) and pigeonpea (Cajanus cajan), growing at a research farm in Dubai (United Arab Emirates) was studied. Eight isolates identified from colony morphology and gram staining reaction, when cultured on yeast extract-mannitol agar medium (YEMA) supplemented with different concentration of sodium chloride (NaCl), produced colonies even at salinities as high as 40 dS m-1. The rhizobial isolates were also found to be effective in nodulating 21-day old seedlings grown in potting soil and irrigated with saline water of up to 12 dS m-1 after inoculation. The tolerance to high levels of salinity and the survival and persistence in severe and harsh desert conditions make these rhizobia highly valuable inoculums to improve productivity of the leguminous plants cultivated under extreme environments.