Region IIa Research Articles

National-scale spatiotemporal patterns of vegetation fire occurrences using MODIS satellite data.

As the risk of climate change increases, robust fire monitoring methods become critical for fire management purposes. National-scale spatiotemporal patterns of the fires and how they relate to vegetation and environmental conditions are not well understood in Zimbabwe. This paper presents a spatially explicit method combining satellite data and spatial statistics in detecting spatiotemporal patterns of fires in Zimbabwe. The Emerging Hot Spot Analysis method was utilized to detect statistically significant spatiotemporal patterns of fire occurrence between the years 2002 and 2021. Statistical analysis was done to determine the association between the spatiotemporal patterns and some environmental variables such as topography, land cover, land use, ecoregions and precipitation. The highest number of fires occurred in September, coinciding with Zimbabwe's observed fire season. The number of fires significantly varied among seasons, with the hot and dry season (August to October) recording the highest fire counts. Additionally, although June, July and November are not part of the official fire season in Zimbabwe, the fire counts recorded for these months were relatively high. This new information has therefore shown the need for revision of the fire season in Zimbabwe. The northern regions were characterized by persistent, oscillating, diminishing and historical spatiotemporal fire hotspots. Agroecological regions IIa and IIb and the Southern Miombo bushveld ecoregion were the most fire-prone areas. The research findings also revealed new critical information about the spatiotemporal fire patterns in various terrestrial ecoregions, land cover, land use, precipitation and topography and highlighted potential areas for effective fire management strategies.

Landscape habitat occupancy and distribution of the Wild Ground Pangolin (Smutsia temminckii) in Zimbabwe’s Protected Areas (PAs)

The Smutsia temminckii is the only species of pangolin known to exist in Zimbabwe and is considered vulnerable under the IUCN Red List of threatened species. Distribution of wild S. temminckii in protected areas (PAs) and associated environmental variables are not well defined in Zimbabwe. The study sort to relate key environmental variables (Altitude, rainfall, temperature and vegetation type) to habitat occupancy and distribution of S. temminckii. Data was collected from forty-eight stations based on S.temminckii sightings historical records spanning ten years (2011-2021) done by field rangers, tourists and scientific services research personnel. A review of available literature was done from online sources and station records. A distribution map based on S. temminckii sightings across various PAs in Zimbabwe was developed for this study. Results of this study reveal that S. temminckii occupy PAs in South East low-veld areas, Northwestern Zimbabwe, Mid Zambezi Valley and Nyanga NP. No historical data on S. temminckii sighting in central PAs located in ecological regions IIa, IIb and III of Zimbabwe. Climatic conditions associated with S. temminckii distribution, except for Nyanga NP, are average temperatures above 220C and rainfall between 400mm to 900mm per annum. Landscapes ideal for S. temminckii habitat occupancy have an altitude between 262m-2000m above sea level. Associated vegetation types for habitat occupancy of S. temminckii are the Zambezian and mopane woodlands as well as montane forest grasslands mosaic of Nyanga NP. Future studies should focus on establishing distribution of S. temminckii outside PA, population status and density to inform conservation of this rare and unique species around Zimbabwe.

Carotid Body Tumor - radiological imaging and genetic assessment.

Carotid Body Tumor i.e. Paraganglioma is a challenging entity from the point of multidisciplinary diagnosis. The main treatment option i.e. surgery yields intraoperative risk,related to cranial nerve palsy and vascular morbidity.Bifurcation of Common Carotid Artery especially at the Carotid Body is the place where Head and Neck Paraganglioma is most frequently seen i.e. 60% of incidence [19]. Indeed, the knowledge of genetic germline SDH mutations, which cause deregulation of hypoxia-induced factors yields better understanding of the tumor nature. It is recommended to conduct selective neck dissection in regions IIA, IIB, III to exlude malignant transformation and metastasis, due to malignant potential of Carotid Body Tumors, especially in case of SDHB mutation. SDHD mutation is the main cause of hereditary HNPGLs. Computed tomography (CT), magnetic resonance imaging (MRI) and angiography yield thorough assessment of paraganglioma extension. In large size tumors, embolization of supplying artery under guidance of angiography may be considered. In case of Carotid Body Tumor, differential diagnosis should include: carotid artery aneurysm, lymphadenopathy, Schwannoma of the hypoglossal nerve or acessory thyroid gland.

Para-recurrent lymph node metastasis was a significant predictor for cervical lymph nodes metastasis in thoracic esophageal carcinoma

Objective To evaluate correlation factors of cervical lymph nodes metastasis in thoracic esophageal carcinoma.Methods Local-regional metastasis of lymph node for 126 cases with esophageal squamous cell cancer after surgery from 2004 to 2009 were reviewed.Risk factors of cervical lymph nodes metastasis were examined by multiple Logistic regression analysis.Results In 126 cases,supraclavicular lymph node metastasis rate was 43.7％ (55/126).By logistic regression,none of the primary site,T stage,N stage,histological grade,lymph node metastasis rate,lymph node metastasis degree and number of lymph nodes metastatic field was not the high risk of cervical lymph nodes metastasis.In addition,multivariate analysis found that lymph node metastasis in mediastinum region 1 was high risk factor for lymph node metastasis of region 1 ( x2 =12.14,9.27,P =0.000,0.002),lymph node metastasis in region Ⅲ and region 2 were high risk factors for lymph node metastasis of region Ⅱa ( x2 =14.56,8.27,8.02,3.93,P =0.000,0.004,0.005,0.047 ).Conclusion Mediastinal para-recurrent nerve lymph node metastasis is a significant predictor for cervical lymph nodes metastasis. Key words: Esophageal neoplasms/surgery; Neoplasms meatstasis,neck lymph nodes; Neoplasms metastasis,para-recurrent nerve lymph node

Rainfall uncertainty in the Mediterranean: dryness distribution

Dryness analysis is a major topic in the study of rainfall regime, mainly in regions with water shortage. The present study suggests a new approach for analyzing dry spells and their annual distribution and introduces a new term: dry days since last rain (DDSLR hereafter). The main goals of this study are to analyze and present the different annual courses of the DDSLR across the Mediterranean region. Daily rainfall totals for the period of 1931–2006 at 41 stations served as the main database. Two annual courses of the DDSLR, the median (50 percentile) and the 90 percentile, are presented for each Julian day in each station. Correlation matrices between stations according to their annual courses were calculated. A cluster analysis was performed on these correlations matrices according to which the stations were grouped. The main conclusions of the present study can be summarized as follows: Four regions were found in the Mediterranean basin according to their annual course of the DDSLR: Region Ia spread over the southern Mediterranean and has the most severe dryness conditions reaching maximum dryness in August and September. Region Ib is located mainly in northeastern Iberian Peninsula, south France, and northwestern Italy. Dryness is less severe than in Region Ia. The maximum dryness conditions are in July and August. Region IIa is located in the northeastern study area, with a bi-modal moderate dryness conditions. Maximum dryness is in August–October and a secondary dry period in January–March. Region IIb is located in the northwestern study area with a bi-modal moderate dryness conditions. Maximum dryness is in January–March and a secondary dry period in October. Both regions Ia and Ib can be combined into a single major region I. This region represents the classical Mediterranean rainfall regime with a very distinguishable dry period during summer. Similarly, regions IIa and IIb can be combined into a single major region II. This region benefits from rainfall all year round and therefore is not considered as having a classical Mediterranean climate. Uncertainty regarding the DDSLR distribution (from year to year) is much crucial in region II, since ecosystems are not adapted to long dry periods and their prolongation may have very severe environmental consequences.

Population Structure and Genetic Diversity ofClintonia udensisTrautv. et Mey. (Liliaceae)

The genetic diversity of 17 populations of Clintonia udensis Trautv. et Mey. was studied by using 15 intersimple sequence repeat primers. The results revealed a relatively high genetic diversity, with percentage of polymorphic $$\mathrm{bands}\,=98.8\% $$ , Shannon’s information $$\mathrm{index}\,=0.56$$ , and Nei’s gene diversity $$\mathrm{index}\,=0.38$$ . The genetic diversity at the population level was considerably low, while a high level of genetic differentiation among populations was detected. This was confirmed by analysis of molecular variance (AMOVA). No significant statistical difference was found between geographic regions. Tetraploid populations showed an approximately equal level of genetic diversity compared with that of the diploid populations. No significant differentiation occurred between cytotypes. Shannon diversity index, Nei’s gene diversity index, and AMOVA analysis all showed that there was more genetic variation among diploid/tetraploid populations than within diploid/tetraploid populations. The Mantel test revealed no significant correlation between genetic distance and geographic distance at the species level. The biological characteristics of this species, the unique Clintonia‐type megasporogenesis and genetic drift, might account for the existence of relatively high interpopulation genetic variation. Cluster analysis gathered the 17 populations into two groups. Group I contained all diploids and made up geographic region I. This might be the center of origin of C. udensis. Group II had two coexisting cytotypes and made up geographic region IIa, IIb‐1, and IIb‐2, which might represent the secondary diversity centers of C. udensis.

Ineffective nodulation ofSesbania macrocarpabySinorhizobium melilotistrain RCR2011

Sinorhizobium meliloti is a well-known symbiont that fixes nitrogen with plants of three genera of the family Leguminosae, Tribe Trifolieae: Medicago, Melilotus, and Trigonella. We have found that S. meliloti strain RCR2011 forms ineffective nodules on a distantly related legume species, Sesbania macrocarpa. Nodules are indeterminate and lack leghemoglobin. Although S. meliloti deformed root-hairs of S. macrocarpa, infection threads were not detected in these cells. Instead, cells of S. meliloti were found in infection pockets between cortical cells and within infection threads that had penetrated into these cells. Bacteria eventually were released and gave rise to symbiosomes, which contained large quantities of an amorphous matrix with parallel arrays of electron-dense striations. Mutants of strain RCR2011 lacking nodA or nodH failed to nodulate S. macrocarpa, inactivation of nodG or nodE resulted in smaller nodules, while inactivation of region IIa, which contains nodIJ, had no apparent effect on nodulation.

Ineffective nodulation of Sesbania macrocarpa by Sinorhizobium meliloti strain RCR2011

Sinorhizobium meliloti is a well-known symbiont that fixes nitrogen with plants of three genera of the family Leguminosae, Tribe Trifolieae: Medicago, Melilotus, and Trigonella. We have found that S. meliloti strain RCR2011 forms ineffective nodules on a distantly related legume species, Sesbania macrocarpa. Nodules are indeterminate and lack leghemoglobin. Although S. meliloti deformed root-hairs of S. macrocarpa, infection threads were not detected in these cells. Instead, cells of S. meliloti were found in infection pockets between cortical cells and within infection threads that had penetrated into these cells. Bacteria eventually were released and gave rise to symbiosomes, which contained large quantities of an amorphous matrix with parallel arrays of electron-dense striations. Mutants of strain RCR2011 lacking nodA or nodH failed to nodulate S. macrocarpa, inactivation of nodG or nodE resulted in smaller nodules, while inactivation of region IIa, which contains nodIJ, had no apparent effect on nodulation.

Tension-compression fatigue behavior of a unidirectional titanium-matrix composite at elevated temperature

The fatigue behavior of a unidirectional metal-matrix composite, SCS-6/Ti-I5-3, has been investigated under tension-compression cycling at 427 °C. This behavior can be categorized into three regions on a fatigue life diagram. Region I, at higher stress levels, would be controlled by fiber fracture. At intermediate stress levels, Region II involved damage mechanisms which were dominated by matrix failure. Two distinct damage mechanisms were observed in this region, region IIa involving little matrix cracking while region IIb consisted of considerable matrix cracking. Region III was below the fatigue limit of the matrix material resulting in fatigue lives longer than one million cycles. Tension-tension fatigue tests were also conducted at 427 °C to compare damage mechanisms and fatigue lives with those under tension-compression loading conditions. On a maximum stress or strain basis, the fatigue life under fully-reversed, tension-compression cycling is less than that for tension-tension cycling. However, on the basis of stress or strain range, the fatigue life under tension-tension cycling is less than that for tension-compression cycling.

Epitope mapping and binding analysis of insulin-specific monoclonal antibodies using a biosensor approach

Molecular interactions between the human insulin molecule and a panel of seven monoclonal antibodies (mAbs) against insulin were investigated by surface plasmon resonance. Using real-time analysis (BIAcore technology), the antigenic sites recognized on the human insulin molecule by these mAbs were mapped. Three overlapping regions could be defined on the insulin molecule coupled to the dextran matrix on the basis of its recognition by three mAbs groups: group I (mAbs 19, 10), group II (mAbs 13, 5, 25, 15) and group III (mAb P10). The antigenic determinants of the molecule in solution were mapped using a two-site assay in which insulin was presented to each mAb, bound to a rabbit anti-mouse IgG Fcγ1 coupled to the dextran. Four antigenic regions were defined: regions I and III were defined by the same antibodies as above whereas region II was recognized differently by mAbs 13, 5 (region IIa) and mAbs 25,15 (region IIb). The K a value of the mAbs determined using the BIAcore were in the same range (from 3 × 10 7 M −1 to 6.6 × 10 9 M −1) whether insulin was coupled to the dextran matrix or in solution. Furthermore, mAbs 19 and P10, which recognize two distinct regions on the insulin molecule, were selected to develop a highly sensitive immunoassay for measurement of insulin in serum.

The bending fatigue behaviour of unidirectionally reinforced SCS6/Ti-15-3

The fatigue behavior of a unidirectional metal-matrix composite, SCS-6/Ti-I5-3, has been investigated under tension-compression cycling at 427 °C. This behavior can be categorized into three regions on a fatigue life diagram. Region I, at higher stress levels, would be controlled by fiber fracture. At intermediate stress levels, Region II involved damage mechanisms which were dominated by matrix failure. Two distinct damage mechanisms were observed in this region, region IIa involving little matrix cracking while region IIb consisted of considerable matrix cracking. Region III was below the fatigue limit of the matrix material resulting in fatigue lives longer than one million cycles. Tension-tension fatigue tests were also conducted at 427 °C to compare damage mechanisms and fatigue lives with those under tension-compression loading conditions. On a maximum stress or strain basis, the fatigue life under fully-reversed, tension-compression cycling is less than that for tension-tension cycling. However, on the basis of stress or strain range, the fatigue life under tension-tension cycling is less than that for tension-compression cycling.

Conserved and Variant Epitopes of Target Antigens of Transmission-Blocking Antibodies among Isolates of Plasmodium falciparum from Malaysia

Monoclonal antibodies (MAbs) directed against different epitope regions on three sexual stage-specific gamete surface proteins of Plasmodium falciparum, Pfs 25, Pfs 230, and Pfs 48/45, were used to study the genetic diversity of these epitopes among fresh isolates of P. falciparum from Malaysia, using immunofluorescence microscopy (IFA). Among 45 Malaysian isolates, one epitope of Pfs 25, designated region I, showed evidence of variable reactivity with MAbs among different isolates; the Pfs 25 epitope, region II, was universally recognized by MAbs in all isolates. Two apparently distinct epitope regions of Pfs 230 were defined by MAbs, one of which was universally recognized by MAbs among the 45 isolates; the other was conserved in all but three isolates. The epitope regions of gamete-surface protein Pfs 48/45, designated regions I, IIa, IIb, IIc, III, and IV, were examined for reactivity by IFA in 33 isolates. Epitope regions I, IIb, III, and IV were conserved in all isolates; regions IIa and IIc existed in variant forms.

α Grain size and β volume fraction aspects of the superplasticity of Ti-6Al-4V

The elevated temperature deformation behaviour of Ti-6Al-4V has been investigated in the temperature range between 775 and 925 °C and for true strain rates 2 × 10−5 to 0.005 s−1. Region III was characterized by m = 0.13 and Q = 602 kJ mol−1. Region II is subdivided into a low temperature region IIa and a high temperature region IIb. Region IIa is characterized by m = 0.77, Q = 216 kJ mol−1 and relatively low ductility while region IIb is characterized by n = 1.3, and identical value of Q and high ductility. Low and high β-phase proportions are responsible for regions IIa and IIb respectively. An apparent region I was accounted for by concurrent grain growth utilizing a grain size sensitivity parameter which is dependent on the β-phase volume fraction. The strain rate-temperature regimes of regions IIa, IIb and III are illustrated in a “region” map.

Role of the nodD and syrM genes in the activation of the regulatory gene nodD3, and of the common and host‐specific nod genes of Rhizobium meliloti

To analyse the regulation of the nodulation (nod) genes of Rhizobium meliloti RCR2011 we have isolated lacZ gene fusions to a number of common, host-range and regulatory nod genes, using the mini-Mu-lac bacteriophage transposon MudII1734. Common (nodA, nodC, nod region IIa) and host-range (nodE, nodG, nodH) genes were found to be regulated similarly. They were activated (i) by the regulatory nodD1 gene in the presence of flavones such as chrysoeriol, luteolin and 7,3',4'-trihydroxyflavone, (ii) by nodD2 in the presence of alfalfa root exudate but not with the NodD1-activating flavones, and (iii) by the regulatory genes syrM-nodD3 even in the absence of plant inducers. Thus common and host-range nod genes belong to the same regulon. In contrast to the nodD1 gene, the regulatory nodD3 gene was not expressed constitutively and exhibited a complex regulation. It required syrM for expression, was activated by nodD1 in the presence of luteolin and was positively autoregulated.

多軸応力下での疲労き裂成長速度におよぼす応力成分相互作用効果

Multiaxial fatigue tests were carried out to investigate the effect of stress components (Δσ, Δτ, σst., τst.) on fatigue crack growth.The test method was the combined tension and tortion one in phase loading by using thin-walled hollow cylindrical specimens with pre-cracks. The experiments were carried out under the condition of equal equivalent stress amplitude, Δσeq=√Δσ2+3Δτ2Under the condition of mixed modes, the fatigue crack growth rate increases remarkably with increasing stress ratio. This characteristics is due to the effect of static tensile stress σst. on Δτ.In this paper, the effect of static tensile stress was incorporated in the constitutive equation of fatigue crack growth rate under the mixed mode fatigue condition of Δσ and Δτ. Then, the following constitutive equation of fatigue crack growth rate including the effects of Δσ, Δτ, σst. and τst. was obtained.db/dN=A(ΔKIb)mA=(AR=0)1/r*r*={1+(σst/Δτ)1/2/7 (Region IIa) 1 (Region IIb)AR=0={2.16×10-5×0.230m (Region IIa) 3.64×10-5×0.147m (Region IIb)m={f(σ2/σ1) (Region IIa) g(σ2/σ1) (Region IIb)

Feedback regulation of nodule formation in alfalfa

When high dosages of wild-type Rhizobium meliloti RCR2011 were inoculated at two different times, 24 h apart, onto either the primary roots of alfalfa (Medicago sativa L.) seedlings or onto lateral roots on opposite sides of a split-root system, the number of nodules generated by the second inoculum was much smaller than the number generated by the first inoculum. These results provide evidence that alfalfa has an active, systemic mechanism for feedback control of nodulation. Non-nodulating mutants and delayed, weakly nodulating mutants did not elicit a discernable suppression of nodulation by subsequently inoculated wild-type cells. An appreciable number of Rhizobium infections thus seem required to elicit the suppressive response. Mutants in nodulation regions IIb and IIa nodulated extensively in the initially susceptible region of the root, but nodule initiation by these mutants was 100-1000 times less efficient, respectively, than the parent. Nodules formed by these mutants emerged 1 d later than normal. The IIb mutants elicited a relatively strong suppression of nodulation in younger parts of the root, but region-IIa mutants elicited only a weak response. These results indicate that elicitation of the regulatory response need not be proportional to nodule formation and imply that genes in region IIa play an important role in elicitation. At high dosages, the region-II mutants induced the development of thick, short roots in a considerably higher percentage of plants than the wild-type bacteria. Nodules generated by wild-type isolates and region-II mutants did not emerge in strict acropetal sequence, probably because some infections developed more slowly than others. Prior exposure of the root to non-nodulating mutants resulted in nodulation by the parent in regions of the root otherwise too mature to be susceptible, indicating that exposure to these mutants may affect the sequence of root development.

Promoters and heterogeneous 5′ termini of the messenger RNAs of adenovirus serotype 2

Adenovirus serotype 2 messenger RNAs are transcribed from nine separate transcription units, which function during early, intermediate and late stages of infection. We have sequenced capped 5′ termini of messenger RNAs from each of these transcription units, and located the templates for each capped terminus in the sequence of the Ad2† genome. These results define the putative initiation sites and promoters for all major Ad2 transcripts. By comparing the termini and promoter DNA sequences, we conclude that seven of nine initiation sites including EIa, EIb, PIX, major late, EIII, EIV and the late form of region IIa mRNA have clearly defined “TATA” box homologies. With early region IIa and IVa2, this homology is absent. For most messengers, the mRNA terminus is microheterogeneous, and encoded within a two to seven-base cap region located ~30 nucleotides downstream from the TATA box. However, the two transcription units that lack TATA boxes display equivalent microheterogeneity. Purine termini are greatly favored over pyrimidine termini. We propose a model for Ad2 cap site recognition in which RNA polymerase scans short DNA segments for purine starts, and discuss the model in the context of EIV mRNAs of Ad2 and Ad5, which differ in their promoter region DNA sequence.